A musician flies from England to Canada where the voltage is 120 VAC. Her amplifier operates on 240 VAC. In order to use her amp, she uses a step-down transformer that has turns on the primary coil and 600 turns on the secondary coil.

answer; maintain a safe following distance;

ans.

heterothermic organisms include those organisms that can switch between homeothermic (having body temperature higher than environment) and poikilothermic (having variation in internal body temperature) strategies.

some migratory birds show heterothermy as they decrease their metabolic rate during cold nights to keep their body temperature low. drop in metabolic rate allows increase in production efficiency of birds that reduces the internal body temperature to make it equal to external cold temperature during cold nights.

thus, the correct answer is 'birds allow their temperature drop in order to increase their production efficiency.'