What was your profit or loss over the day (in $)?

profit or loss over the day (in $) is the subtraction of sell price(in $) from the purchase price(in $) at the end of the day.

Explanation:

To find the percentage of profit or loss we first find the profit or loss by the  subtraction of sell price from the purchase price and than divide the result by the purchase price and multiply with 100.

Formoula for finding the percentage profit or loss= (sell price- purchase price)*100/(purchase price)

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.'