If a negative externality exists, then there is a when society produces the market output instead of the socially optimal output. This exists because the to sellers and third parties are the derived by buyers.
a. net social benefit; costs; greater than; benefits
b. net social cost; benefits; less than; costs
c. net social cost; costs; greater than; benefits
d. net social cost; costs; less than; benefits
e. none of the above

Option "A" is correct.

Explanation:

net social benefit; costs; greater than; benefits

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.'

answer; competency based pay;