C. Decreased death rate is the answer
The elephants skull, I believe.
The given diagram is food chain. Food chain is a sequence of populations or organisms of an ecosystem through which the food and its contained energy passes with each member becoming the food of a later membre of the sequence. The number of trophic levels in a food chain is 3-6 and in each trophic level a lot of biomass is consumed in liberating energy.
In the above food chain plants( producers) radiant light energy into chemical form. Rodents are primary consumer, owl is a secondary consumers or primary carnivores and wolf is a tertiary consumer or secondary carnivores.
