Like Leonardo said that water is the driver of nature, it proceeds life forward in the right direction and the worst part is that we never understand its importance. We are like the passenger who is sitting behind in his seat relaxing and never understand the efforts put by the driver to move the vehicle forward. But it’s time for us to understand that life can’t continue without water and we have to save it. It’s our planet, it’s our water and only we are responsible for its conservation.

1. 11
SAVE WATER!SAVE WATER!
SAVE LIFE!SAVE LIFE!

2. 2
PlanPlan
– In our presentation, we will follow the following plan:In our presentation, we will follow the following plan:
• 1) Water as the cradle of life1) Water as the cradle of life
• 2) Physical and chemical properties of water2) Physical and chemical properties of water
• 3) Pollution of water3) Pollution of water

3. 33
Water – the cradle of lifeWater – the cradle of life
Part 1Part 1

4. 4
Water – the cradle of lifeWater – the cradle of life
• For proving the importance of water for the birth of life, we will take aFor proving the importance of water for the birth of life, we will take a
look at the as known chemical evolution – the transition fromlook at the as known chemical evolution – the transition from
inorganic materials to the simplest and fundamental form of life asinorganic materials to the simplest and fundamental form of life as
we know it – the first cells.we know it – the first cells.
• The cells are the basic structure, metabolic and functional unit ofThe cells are the basic structure, metabolic and functional unit of
organisms.organisms.
• The evolution of life after the creation of cells is known as biologicalThe evolution of life after the creation of cells is known as biological
evolution, and we are not going into it in this presentation.evolution, and we are not going into it in this presentation.

5. 5
This tree shows the
evolution of primary
chemical elements until
the forming of life as we
know it. Notice that the
greater part of evolution is
before the formation of the
first cells.

6. 6
First cells
Primary Earth
Chemical
evolution
Biological
evolution
Conventional border
Protobionts
Low mass
organic
Initial gases
Biopolymers
CO
H2O
CO
2
NH3
H2 CH
4
NO2
aggregates
Biopolymers
Protobionts
1
2
3
4
5
Life as we know it
N2

7. 7
Initial gasesInitial gases
1 stage1 stage
• 1.1. Probably during the early stages ofProbably during the early stages of the Earth’s existence therethe Earth’s existence there
were violent volcanic eruptions on the whole surface, congestion ofwere violent volcanic eruptions on the whole surface, congestion of
the Earth’s crust and separation of a high amount of heat. Thethe Earth’s crust and separation of a high amount of heat. The
gases (water vapours, hydrogen, methane, ammonia), coming fromgases (water vapours, hydrogen, methane, ammonia), coming from
the hot semi-fluid interior of the Earth, formed the atmosphere. Itthe hot semi-fluid interior of the Earth, formed the atmosphere. It
contained the basic materials for the formation of organiccontained the basic materials for the formation of organic
combinations.combinations.
Active volcanoes
CO
H2O
CO
2NH3
H2
CH
4
NO2
N2

8. 8
2 stage2 stage
• The gThe gases, contained in the atmosphere,ases, contained in the atmosphere, reacted with each otherreacted with each other
and formed organic molecules. The energy for this synthesis cameand formed organic molecules. The energy for this synthesis came
from the lightning and the ultra-violet radiation.from the lightning and the ultra-violet radiation. Gradually the EarthGradually the Earth
became cold and when the temperature fellbecame cold and when the temperature fell belowbelow 100˚С100˚С, the water, the water
vapours began to condense, the rain evaporated from the hotvapours began to condense, the rain evaporated from the hot
surface and this initiated the circle of water.surface and this initiated the circle of water. The folding proccessesThe folding proccesses
led to the forming of giant hollows. They filled with water and formedled to the forming of giant hollows. They filled with water and formed
the oceans and the seas.the oceans and the seas.
Methane
Benzene
Soap

9. 9
Miller’s experimentMiller’s experiment
• An evidence for this is theAn evidence for this is the
experiment of Stanley Miller. Heexperiment of Stanley Miller. He
invented a device in whichinvented a device in which
ammonia, methane, hydrogen andammonia, methane, hydrogen and
water vapours circulated andwater vapours circulated and
through the mixture passed anthrough the mixture passed an
electric spark. During theelectric spark. During the
circulation the water cooled andcirculation the water cooled and
fell like a “rain”. After a week in thefell like a “rain”. After a week in the
liquid were found amino acids. It isliquid were found amino acids. It is
perfectly possible that the sameperfectly possible that the same
processes happened in theprocesses happened in the
atmosphere.atmosphere.

10. 10
3 stage3 stage
• Some primitive nucleic acidsSome primitive nucleic acids acquired matrix ability and were able to form aacquired matrix ability and were able to form a
copy of themselves. The macromolecules with opposite charges stuckcopy of themselves. The macromolecules with opposite charges stuck
together and formed aggregates - complexes of over-molecule level. Thetogether and formed aggregates - complexes of over-molecule level. The
rain carried away the organic combinations in the oceans and the seas,rain carried away the organic combinations in the oceans and the seas,
where the so-called “organic soup” formed.where the so-called “organic soup” formed.
• The simple organic combinations reacted with each other and formedThe simple organic combinations reacted with each other and formed
simplesimple albumenalbumenss, nucleic acid, nucleic acids, carbohydrates and lipids, which constantlys, carbohydrates and lipids, which constantly
evolved. The albumens formedevolved. The albumens formed hydrophilichydrophilic colloidal complexes, whichcolloidal complexes, which
attracted the water molecules.attracted the water molecules.

11. 11
• On the surface of some coacervates more lipids and albumens gatheredOn the surface of some coacervates more lipids and albumens gathered
and formed a double molecule layer. With time the cover of someand formed a double molecule layer. With time the cover of some
coacervates became permeable and some reactions which released energycoacervates became permeable and some reactions which released energy
began. The membrane gave stability to the coacervates. This is thebegan. The membrane gave stability to the coacervates. This is the
precellular period in the evolution of organic matter.precellular period in the evolution of organic matter.
4 stage4 stage
• Enzymes were formed in the coacervates through absorbing metal ions.Enzymes were formed in the coacervates through absorbing metal ions.
Some combinations of the organic molecules in the coacervatesSome combinations of the organic molecules in the coacervates becamebecame
stable andstable and added to theiradded to their organization, while others were destroyed. Theorganization, while others were destroyed. The
complexes of over-molecule level in them were much more complicatedcomplexes of over-molecule level in them were much more complicated
than these in the environment.than these in the environment.
• The coacervates are very small drops, which have osmotic characteristics.The coacervates are very small drops, which have osmotic characteristics.
Around the complexes of over-molecule level a water cover differentiated. InAround the complexes of over-molecule level a water cover differentiated. In
this system the molecules interacted with each other and new moleculesthis system the molecules interacted with each other and new molecules
entered through the cover, thus enlarging the drop.entered through the cover, thus enlarging the drop.
Coacervate

12. 12
5 stage5 stage
• Molecules which already existed in the organic soup and could replicateMolecules which already existed in the organic soup and could replicate
were included in the coacervates. As a result of this awere included in the coacervates. As a result of this a rearrangement of therearrangement of the
interior contents began. The transport ofinterior contents began. The transport of materials through the cellularmaterials through the cellular
membrane perfected. The nucleic acids established control over the basicmembrane perfected. The nucleic acids established control over the basic
life processes. The protocells could split and share their genetic programlife processes. The protocells could split and share their genetic program
with their filial cells. The cellular period of the evolution of the animatewith their filial cells. The cellular period of the evolution of the animate
nature began.nature began.

13. 13
• …… and life began …and life began …

14. 1414
Properties of waterProperties of water
Part 2Part 2

15. 15
Water has no taste, no coloWater has no taste, no colouur, no odor, no odouur; it cannot be defined,r; it cannot be defined,
art relished while ever mysterious.art relished while ever mysterious.
NNot necessary to life, but rather life itself. It fills us with a gratificationot necessary to life, but rather life itself. It fills us with a gratification
that exceeds the delight of the senses.that exceeds the delight of the senses.
ANTOINE DE SAINT-EXUPERY (1900-1944), Wind, Sand, and Stars, 1939ANTOINE DE SAINT-EXUPERY (1900-1944), Wind, Sand, and Stars, 1939

16. 16
Planet, dominated by waterPlanet, dominated by water
• We live on a planet that isWe live on a planet that is
dominated by waterdominated by water..
• More than 70% of the Earth's surface isMore than 70% of the Earth's surface is
covered with this simple molecule. Scientistscovered with this simple molecule. Scientists
estimate that theestimate that the hydrospherehydrosphere containscontains
about 1.36 billion cubic kilometers of thisabout 1.36 billion cubic kilometers of this
substance mostly in the form of a liquidsubstance mostly in the form of a liquid
(water) that occupies topographic(water) that occupies topographic
depressions on the Earth. The second mostdepressions on the Earth. The second most
common form of the water molecule on ourcommon form of the water molecule on our
planet isplanet is iceice. If all our planet's ice melted. If all our planet's ice melted,,
sea-levelsea-level would rise by about 70 meters.would rise by about 70 meters.

17. 17
• Water is also essential for life.Water is also essential for life.
Water is the major constituent ofWater is the major constituent of
almost all life forms. Most animalsalmost all life forms. Most animals
and plants contain more than 60%and plants contain more than 60%
water by volume. Without water lifewater by volume. Without water life
would probably never havewould probably never have
developed on our planet.developed on our planet.

18. 18
Structure of water moleculeStructure of water molecule
• The two hydrogen atoms bound to one oxygenThe two hydrogen atoms bound to one oxygen
atom to form a 'V' shape with the hydrogenatom to form a 'V' shape with the hydrogen
atomsatoms at an angle of 105°.at an angle of 105°.
• When the hydrogen atoms combine with oxygen,When the hydrogen atoms combine with oxygen,
they each give away their single electron andthey each give away their single electron and
form a covalent bond.form a covalent bond. Because electrons areBecause electrons are
more attracted to the positively charged oxygenmore attracted to the positively charged oxygen
atom, the two hydrogensatom, the two hydrogens become slightlybecome slightly
positively charged (they give away their negativepositively charged (they give away their negative
charge) and the oxygen atom becomescharge) and the oxygen atom becomes
negatively charged.negatively charged.
Oxygen atom
Hydrogen atom
Covalent bond

19. 19
+
--
Polar moleculePolar molecule
• This separation between negative and positive chargesThis separation between negative and positive charges
produces a polar molecule, that is aproduces a polar molecule, that is a molecule that has anmolecule that has an
electrical charge on its surface.electrical charge on its surface. The hydrogen lobes haveThe hydrogen lobes have
positive charges, and the oxygen atom on the opposite sidepositive charges, and the oxygen atom on the opposite side
has twohas two negative charges (associated with two lobes.negative charges (associated with two lobes.))

20. 20
Hydrogen bondHydrogen bond
• Because they are polarized, twoBecause they are polarized, two
adjacent H2O molecules can form aadjacent H2O molecules can form a
linkage known as a hydrogenlinkage known as a hydrogen bond.bond.
• Hydrogen bonds have only aboutHydrogen bonds have only about
1/20 the strength of a covalent bond.1/20 the strength of a covalent bond.
A hydrogen bond is therefore a weakA hydrogen bond is therefore a weak
chemical bond between a hydrogenchemical bond between a hydrogen
atom in one polaratom in one polar mmolecule and aolecule and a
very electronegative atom of avery electronegative atom of a
second polar molecule.second polar molecule. TheThe
hydrogen of one water molecule willhydrogen of one water molecule will
be attracted to the oxygen of anotherbe attracted to the oxygen of another
water molecule.water molecule. TheTherere are usually 4-are usually 4-
8 molecules per group in liquid water.8 molecules per group in liquid water.
+
-

21. 21
• The water molecules form hydrogen bonds, giving shape toThe water molecules form hydrogen bonds, giving shape to
water as a liquid.water as a liquid. Each single water molecule can formEach single water molecule can form
bonds with four other water molecules in a tetrahedralbonds with four other water molecules in a tetrahedral
arrangement. Although these bonds are weak they lead toarrangement. Although these bonds are weak they lead to
many other unique properties.many other unique properties.

22. 22
3 aggregate conditions3 aggregate conditions
• Water is unique in that it is theWater is unique in that it is the
only natural substance that isonly natural substance that is
found in all three states -- liquid,found in all three states -- liquid,
solid (ice), and gas (steam) -- atsolid (ice), and gas (steam) -- at
the temperatures normally foundthe temperatures normally found
on Earth. This is becauseon Earth. This is because thethe
Earth is a very special planet withEarth is a very special planet with
just the right range ofjust the right range of
temperatures and air pressures.temperatures and air pressures.
Earth's water is constantlyEarth's water is constantly
interacting, changing, andinteracting, changing, and inin
movement.movement.
 Water cycle.
• Water is found on Earth in all threeWater is found on Earth in all three
forms: liquid, solid, gas, and isforms: liquid, solid, gas, and is
cycled though the water cyclcycled though the water cycle.e.

23. 23
Water propertiesWater properties
• Water is a tasteless, odourless liquidWater is a tasteless, odourless liquid
at ambient temperature and pressure,at ambient temperature and pressure,
and appears colourless, although itand appears colourless, although it
has its own intrinsic very light bluehas its own intrinsic very light blue
hue. Ice also appears colohue. Ice also appears colouurless, andrless, and
water vapor is essentially invisible aswater vapor is essentially invisible as
a gas.a gas.
• TastelessTasteless
• OdourlessOdourless
• ColourlessColourless
• Water as a liquid has the following properties:Water as a liquid has the following properties:

24. 24
TransparencyTransparency
• Water is transparent, and thus aquaticWater is transparent, and thus aquatic
plants can live within the water becauseplants can live within the water because
sunlight can reach them. Only strong UVsunlight can reach them. Only strong UV
light is slightly absorbed.light is slightly absorbed.

25. 25
ConductivityConductivity
• Conductivity is the abilityConductivity is the ability
of a substance to carryof a substance to carry
an electric current.an electric current.
• Water will conduct anWater will conduct an
electric current only ifelectric current only if
dissolved ions are presentdissolved ions are present
because water moleculesbecause water molecules
do not act as ado not act as a conductorconductor..
Measuring conductivity isMeasuring conductivity is
a good way to determinea good way to determine
the amount of dissolvedthe amount of dissolved
solids in a sample of watersolids in a sample of water
and, thus, to determine itsand, thus, to determine its
puritypurity..

26. 26
• If water worked like other liquids, thenIf water worked like other liquids, then
there would be no such thing as an icethere would be no such thing as an ice
berg, the ice in your soft drink wouldberg, the ice in your soft drink would
sink to the bottom of the glass, andsink to the bottom of the glass, and
ponds would freeze from the bottom up!ponds would freeze from the bottom up!
The maximum density of water is atThe maximum density of water is at
3.98 °C (39.16 °F).3.98 °C (39.16 °F).
Water’s extensionWater’s extension
• Water becomes even less dense uponWater becomes even less dense upon
freezing, expanding 9%. This causesfreezing, expanding 9%. This causes
an unusual phenomenon: ice floatsan unusual phenomenon: ice floats
upon water, and so water organismsupon water, and so water organisms
can live inside a partly frozen pondcan live inside a partly frozen pond
because the water on the bottom has abecause the water on the bottom has a
temperature of around 4 °C (39 °F).temperature of around 4 °C (39 °F).
• Most liquids contract (get smaller) when they get colder. Water is differentMost liquids contract (get smaller) when they get colder. Water is different --
itit contracts until it reaches 4 C then it expands until it is solid. Solid water iscontracts until it reaches 4 C then it expands until it is solid. Solid water is
less dense thaless dense thann liquid water because of this.liquid water because of this.
• The higher boiling point and melting point ofThe higher boiling point and melting point of
water can be explained by the hydrogenwater can be explained by the hydrogen
bonds that help hold groups of waterbonds that help hold groups of water
molecules together. These hydrogen bondsmolecules together. These hydrogen bonds
must be broken before water molecules canmust be broken before water molecules can
escape into the air. This requires energy inescape into the air. This requires energy in
the form of heat. Molecules such as sulfurthe form of heat. Molecules such as sulfur
dioxide and carbon dioxide do not havedioxide and carbon dioxide do not have
hydrogen bonds and, consequently, requirehydrogen bonds and, consequently, require
less energy to boil.less energy to boil.
• Hydrogen bonding accounts for theHydrogen bonding accounts for the
strength of fibres in wood. It also helpsstrength of fibres in wood. It also helps
explain some of the physicalexplain some of the physical
characteristics of water. Water boils atcharacteristics of water. Water boils at
100°C and freezes at 0°C. By comparison,100°C and freezes at 0°C. By comparison,
sulfur dioxide, a molecule of similar size,sulfur dioxide, a molecule of similar size,
boils at 62°C and freezes at -83°C.boils at 62°C and freezes at -83°C.

27. 27
Thermal capacityThermal capacity
• Water has one of the highest heatWater has one of the highest heat
capacities of all substances.capacities of all substances.
• The large amount of water onThe large amount of water on
Earth means that extremeEarth means that extreme
temperature changes are rare ontemperature changes are rare on
Earth compared to other planets.Earth compared to other planets.
• This means that it takes a great deal ofThis means that it takes a great deal of
heat energy to change the temperatureheat energy to change the temperature
of water compared to metals.of water compared to metals.

28. 28
Thermal bufferThermal buffer
• Were it not for the high heat capacity of water, our bodies (whichWere it not for the high heat capacity of water, our bodies (which
also contain a large amount of water) would be subject to a greatalso contain a large amount of water) would be subject to a great
deal of temperature variation.deal of temperature variation.
• By the two ways of defending against overheating (high heatBy the two ways of defending against overheating (high heat
capacity and high warmth of evaporation) water actually is an idealcapacity and high warmth of evaporation) water actually is an ideal
medium for life and ensures safe temperature conditions in themedium for life and ensures safe temperature conditions in the
organic systems. Theorganic systems. They alsoy also allow water to moderate Earth's climateallow water to moderate Earth's climate
by buffering large fluctuations in temperature.by buffering large fluctuations in temperature.

29. 29
AdhesionAdhesion
• Water has a partial negative charge (σ-) near the oxygen atom dueWater has a partial negative charge (σ-) near the oxygen atom due toto
the unshared pairs of electrons, and partial positive charges (σ+) nearthe unshared pairs of electrons, and partial positive charges (σ+) near
the hydrogen atoms. In water, this happens because the oxygen atom isthe hydrogen atoms. In water, this happens because the oxygen atom is
more electronegative than the hydrogen atoms — that is, it has amore electronegative than the hydrogen atoms — that is, it has a
stronger "pulling power" on the molecule's electrons, drawing themstronger "pulling power" on the molecule's electrons, drawing them
closer (along with their negative charge) and making the area aroundcloser (along with their negative charge) and making the area around
the oxygen atom more negative than the area around both of thethe oxygen atom more negative than the area around both of the
hydrogen atoms.hydrogen atoms.
• Water molecules stick to each other. This is calledWater molecules stick to each other. This is called
cohesion. Water can also be attracted to other materials.cohesion. Water can also be attracted to other materials.
This is called adhesion.This is called adhesion.

30. 30
Capillary actionCapillary action
• Capillary action is relatedCapillary action is related
to the adhesiveto the adhesive propertiesproperties
of water.of water.
• Plants take advantage ofPlants take advantage of
ccapillary action to pullapillary action to pull
water from thewater from the earthearth intointo
themselves.themselves.
• You can seeYou can see ccapillaryapillary
action 'in action' by placingaction 'in action' by placing
a straw into a glass ofa straw into a glass of
water.water.

31. 31
gravity and the size of the straw.gravity and the size of the straw.
The thinner the straw or tube theThe thinner the straw or tube the
higher uphigher up ccapillary action will pullapillary action will pull
the waterthe water..
The water 'climbs' up the straw.
• Capillary action is limited by ...Capillary action is limited by ...
• What is happening is that the waterWhat is happening is that the water
molecules are attracted to the strawmolecules are attracted to the straw
molecules. When one watermolecules. When one water
molecule moves closer to the strawmolecule moves closer to the straw
molecules the other watermolecules the other water
molecules (which are cohesivelymolecules (which are cohesively
attracted to that water molecule)attracted to that water molecule)
also move up into the straw.also move up into the straw.

32. 32
High surface tensionHigh surface tension
• Surface tension is related to theSurface tension is related to the
cohesivcohesivee propertiesproperties of waterof water
• Water has a very high surfaceWater has a very high surface
tension. In other words, water istension. In other words, water is
sticky and elastic, and tends tosticky and elastic, and tends to
clump together in drops rather thanclump together in drops rather than
spread out in a thin film. Surfacespread out in a thin film. Surface
tension is responsible fortension is responsible for capillarycapillary
actionaction, which allows water (and its, which allows water (and its
dissolved substances) to movedissolved substances) to move
through the roots of plants andthrough the roots of plants and
through the tiny blood vessels in ourthrough the tiny blood vessels in our
bodiesbodies

33. 33
• This phenomenon also causes waterThis phenomenon also causes water
to stick to the sides of verticalto stick to the sides of vertical
structures despite gravity's downwardstructures despite gravity's downward
pull. Water's high surface tensionpull. Water's high surface tension
allows for the formation of waterallows for the formation of water
droplets and waves, allows plants todroplets and waves, allows plants to
move water (and dissolved nutrients)move water (and dissolved nutrients)
from their roots to their leaves, andfrom their roots to their leaves, and
the movement of blood through tinythe movement of blood through tiny
vessels in the bodies of somevessels in the bodies of some
animals.animals.
This insect walks on the water’s surface

34. 34
Universal solventUniversal solvent
• Substances that will mix well and dissolve inSubstances that will mix well and dissolve in
water, e.g. salts, sugars, acids, alkalis, andwater, e.g. salts, sugars, acids, alkalis, and
some gases: especially oxygen, carbonsome gases: especially oxygen, carbon
dioxide (carbonation), are known asdioxide (carbonation), are known as
“hydrophilic" (water-loving) substances, while“hydrophilic" (water-loving) substances, while
those that do not mix well with water (e.g.those that do not mix well with water (e.g.
fats and oils), are known as “hydrophobic"fats and oils), are known as “hydrophobic"
(water-fearing) substances.(water-fearing) substances.
• When a substance dissolves in a liquid,When a substance dissolves in a liquid, thethe
mixture is termed a solution. The dissolvedmixture is termed a solution. The dissolved
substance (in this case sugar) is the solute,substance (in this case sugar) is the solute,
and the liquid that does the dissolving (in thisand the liquid that does the dissolving (in this
case water) is the solvent.case water) is the solvent.
• Water is a very strong solvent, referred to as the universalWater is a very strong solvent, referred to as the universal
solvent, dissolving many types of substances.solvent, dissolving many types of substances.
NaCl
HydrophilicHydrophilicsalts, sugars, acids, alkalis,salts, sugars, acids, alkalis,
and some gasesand some gases
HydrophobicHydrophobicfats and oilsfats and oils

35. 35
• TheyThey dissolve in waterdissolve in water, because, because their molecules separate fromtheir molecules separate from
each other, each becoming surrounded by water molecules.each other, each becoming surrounded by water molecules.

36. 36
pH balancepH balance
• Water in a pure state has a neutralWater in a pure state has a neutral
pHpH. As a result, pure water is. As a result, pure water is
neitherneither acidicacidic nornor basicbasic. Water. Water
changes its pH when substanceschanges its pH when substances
are dissolved in it. Rain has aare dissolved in it. Rain has a
naturally acidic pH of about 5.6naturally acidic pH of about 5.6
because it contains naturalbecause it contains natural
derived carbon dioxide and sulfurderived carbon dioxide and sulfur
dioxide.dioxide.
The pH of a sample of water is a
measure of the concentration of
hydrogen ions.

37. 37
Biochemical reactionsBiochemical reactions
• WWater is a regulator of biochemical reactions. All of them start andater is a regulator of biochemical reactions. All of them start and
complete by direct or indirect reaction with the water molecules incomplete by direct or indirect reaction with the water molecules in
the cell. The speed of the biochemical processes is reduced by thethe cell. The speed of the biochemical processes is reduced by the
reduction of water content under some limitsreduction of water content under some limits..
• With tremendous odds against unicellular organisms, they exudeWith tremendous odds against unicellular organisms, they exude
water, as a result of which the cytosol is condensed and the vitalwater, as a result of which the cytosol is condensed and the vital
processes are reduced to a minimum. This state of organisms isprocesses are reduced to a minimum. This state of organisms is
called 'vita minima' or anabiosis. At optimal living conditions thecalled 'vita minima' or anabiosis. At optimal living conditions the
amount of water in the organisms gets back to normal and theamount of water in the organisms gets back to normal and the
constitution is restored to its normal active state.constitution is restored to its normal active state.

38. 38
AfterwordAfterword
• Once the unique role of water in the living systemsOnce the unique role of water in the living systems waswas
expressed by a prominent biochemist Szent-Dyerdyi in theexpressed by a prominent biochemist Szent-Dyerdyi in the
phrase: “Water is not only a mother, but a matrix of life”. That isphrase: “Water is not only a mother, but a matrix of life”. That is
why everybody should take thoughtwhy everybody should take thought ofof it.it.
• Water is closely connected not only with the birthWater is closely connected not only with the birth ofof life, but withlife, but with
its evolution as well. It has always been a limiting factor. The lackits evolution as well. It has always been a limiting factor. The lack
of water is one of the main forces controlling the natural selection.of water is one of the main forces controlling the natural selection.
All terrestrial organisms take water and preserve it by someAll terrestrial organisms take water and preserve it by some
means or other. Clear examples can easily be found amongmeans or other. Clear examples can easily be found among
desert ones such as cacti and camels.desert ones such as cacti and camels.

39. 39

40. 40
Conclusion :Conclusion :
• Save water!Save water!
• Save life!Save life!
Author: Diana Sofronieva