The answer is A, the immune system
The answer should be C if not then it is D
Answer:
Even though the symptoms of the stimulants and depressants are quite opposite, the causes of these symptoms are completely unrelated. A stimulant could cause one area of the brain to release a chemical and a depressant could affect a completely different area of the brain. They don't have to counteract each other.
Explanation:
Conduct research and experiments to improve the productivity and sustainability of field crops and farm animals
Yelling at everyone in site
throwing stuff
..etc.
