Some factors could be:
weather
ressources
The roots need all the water it can get but sense theres water in the ground it already has water which transports water to the leaves
During puberty the testes of the man will begin to produce testosterone. This causes hair growth in multiple areas of the body and the voice change. Similarly, women begin to grow hair but also begin menstruation.
ANSWER:
c. Figuring out how pesticides affect plant growth.