Psychic stimulants include caffeine, cocaine, and various amphetamines. These drugs are used to enhance mental alertness and reduce drowsiness and fatigue.
The investigators could distinguish human hair from animal hair by the patter of pigmentation and by the medullary index.
The pigmentation in human hairs is denser toward the cuticle, whereas in animal hair is denser toward the medulla. Human hairs are usually one colour throughout the whole length, while animal hairs may change colour suddenly.
The medulla in humans is thinner than in animals: the medullary index for human hairs is 0.33 or less; the medullary index for animal hairs is 0.5 or more.
The physiology, behavior, and other qualities of a particular organism or class of organisms.
Answer:
Adaptations and selective breeding, if that is a choice for you.
Explanation:
The answer is two and four hope this helps
