In the economy of Talikastan in 2015, consumption was $1000, GDP was $1950, government purchases were $500, and investment was $700. What were Talikastan’s net exports in 2015? a. -$250 b. $250 c. $2200 d. Net exports cannot be calculated from the information given.

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.'