I believe the correct response is A. The population of secondary consumers would decrease, as now these organisms can't obtain energy through the food they consume which is the primary consumers as there is none and thus the population in higher tropic level dependent on them would decrease. This is the secondary consumer.
Coenzymes
Coenzymes are small organic molecules that, themselves, do not function as catalysts (i.e. enzymes) but aid the latter in carrying out their functions. Enzymes are biological catalysts, which means that they allow reactions to occur at lower activation energies. In a way, enzymes help to "speed up" chemical reactions.
Coenzymes are mostly derived from vitamins. Examples include TPP from Vitamin B1 (thiamine), FAD from Vitamin B2 (Riboflavin), and NAD+ from Niacin.
Carb digestion happens first in the mouth by amylase. then stomach, pancreas, small intestine, large intestine
