LINKS WILL BE REPORTED PLEASE HELP Certain bacteria live and grow on the roots of some plants and produce chemicals that are beneficial to the plants. Which of the following observations best supports the claim that this relationship is beneficial to the plants?

A. When the bacteria are removed from the plant roots and are grown in a laboratory setting, they fail to survive
B. The population size of the bacteria varies greatly depending on the chemistry of the soil and the type of the plant
C. Plants with a higher density of the bacteria on their roots have increased rates of survival and reproduction
D. The chemical produced by the bacteria can be created by humans and added to the soil where it reaches the roots of the plant