And how would greater amounts of this compound impact plant growth, and why?

a
ATP - decrease plant growth, due to decreased carbon rich compounds and accelerated absorption.
b
Water - increase plant growth, due to greater availability of this carbon rich reactant.
c
Carbon dioxide - increase plant growth, due to greater availability of this essential reactant.
d
Carbon dioxide - decrease plant growth, due to increased respiration.

c

Carbon dioxide - increase plant growth, due to greater availability of this essential reactant.

Carbon dioxide is a key component in photosynthesis, the process by which plants convert sunlight into energy. Increasing the amount of carbon dioxide in the atmosphere provides plants with more of this essential reactant, which can accelerate photosynthesis and lead to increased plant growth.