You disproved your hypothesis. The pika's thyroxine (T3 and T4) hormone levels are the same as similarly-sized mammals that live in warmer habitats. However, the pika's BMR is much higher. Use your knowledge of cell-cell signaling in animals to propose an explanation for how the BMR could be higher in the pika even though the thyroxin levels are similar to other small mammals in warm habitats..
You disproved your hypothesis. The pika's thyroxine (T3 and T4) hormone levels are the same as similarly-sized mammals that live in warmer habitats. However, the pika's BMR is much higher. Use your knowledge of cell-cell signaling in animals to propose an explanation for how the BMR could be higher in the pika even though the thyroxin levels are similar to other small mammals in warm habitats..