D, since it only affects the sex cell which are for forming offspring.
I'd say heat, more specifically sunlight.
Why?
Because sun is the form of energy needed for plants to grow and live. Plants in turn are the form of energy needed for herbivores to live that later on turn out to be the form of energy needed by the carnivores. When these die, decomposers will be the ones to take advantage of the energy.
As you can see an ecosystem has already been formed: producers, secondary consumers, tertiary consumers or decomposers.
Hope it helped,
Happy homework/ study/ exam!
<em>Answer: In dehydration synthesis reactions, a water molecule is formed as a result of generating a covalent bond between two monomeric components in a larger polymer. In hydrolysis reactions, a water molecule is consumed as a result of breaking the covalent bond holding together two components of a polymer.</em>