Answer:
A. The complementary shapes of an enzyme and a substrate
Explanation:
The Lock-and-Key model was made to show how an enzyme's active zone fits a substrate and how they bond together. It correlates just like a lock and a key; you have to have the correct-shaped key in order to open a lock. Same process of thought with the enzymes; you must have the same shape for both in order to bind together,
Each time you exhale, you are releasing carbon dioxide gas (CO2) into the atmosphere. Animals and plants get rid of carbon dioxide gas through a process called respiration. Carbon moves from fossil fuels to the atmosphere when fuels are burned.
I believe its D. response neuron.
Hope this helps!
Love, Grace-