7. Which of the following is an accurate historical perception of play? O Play was discouraged by the French and the Germans.
O Play was discouraged by the ancient Greeks and the
French.
O Play was always encouraged in America, but not in
England.
O Play was discouraged in seventeenth-century England
and by the Puritans in the American colonies.

what are the options

explanation:

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.'