Nicotine is a form of
a. hallucinogens.
b. depressants.
c. stimulants

Nicotine is a form of a stimulant. It is found in the tobacco plant, amongst other plants. It is made in the roots of the plant and accumulates in the leaves of the plants. It is addictive and acts as a stimulant. Tests have shown that it can increase your heart rate as well as your heart muscle's rate of oxygen consumption. In high doses, it can be harmful. It is also effective as an insecticide. Nicotine can also be produced synthetically. 

Answer active artificial immunization;

Ithink that it is the brain.