I need help on this I am confused

I don't see the last image after the snake. Anyway, I would say C because the Snake would eat more Toads, so Snake population would increase.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products

if you know your abc's you should be able to get your answer or just use google