Increasing consumption of one good means consumption of the other good must decrease in order to maintain constant utility. Additionally, individuals experience less marginal utility for each additional unit consumed. These statements explain why indifference curves must be:

a. downward-sloping and concave.
b. downward-sloping and convex.
c. upward-sloping and concave.
d. upward-sloping and convex.

downward-sloping and concave

Explanation:

The indifference curves must be downward-sloping and concave because the  consumption of one product decreases with the rise in the consumption of other product. Marginal utility also adds up to the concave shape of this curve because the goods' consumption is plotted against both axes. Hence, the downward trend represents the inverse proportionality between compared products.

the answer is 10c + 6b = 32

step-by-step 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.'