Hi lovely,
The answer you're looking for would be the activation or inactivation of genes.
Chloroplast is a part in a plant cell. It is the site at which photosynthesis occurs (light energy converted into oxygen).
Answer:
The symbol for D in Brenda's diagram most likely represent the sun.
Reason:
A represents the Universe, B represents the Solar System, C represents the Earth and D represents the Sun
Activation energy Enzymes Reactants/substrates Products Bonds
