As for this problem, the most probable answer and the most likely answer for this one would be D. the effect of pesticides on organisms in the environment.
A toxicologist would only study about chemicals and their effect on organisms in the environment. Pesticides are chemicals made to combat organisms that aren't wanted particular parts of the environment such as crops and rice field. These pesticides don't just affect those organisms that are targeted, but even the users and other organisms that may have come in contact with pesticides.
Two adaptations of a saguaro cactus in order to store water are as following:
1. large stems can store water.
2.thick waxy skin in order to reduce water loss through pores.
It will be a Compound, because it will use Multiple Optical lenses
B that our early ancestors were tailed primates
