HANS SELYE was the one who defined stress in this way.
Hans Selye is an endocrinologist and a famous stress researcher. He was the first scientist to write about the general adaptation syndrome which he used to explain his stress model. His model put it forward that an event which threaten the well being of a living organism leads to three stage bodily response which are alarm, resistance and exhaustion stage.
Answer:
Skin serves as a protective barrier, a way to sense the world, and a layer that keeps nutrients and water inside the body. Four types of cells make up the skin, and they are produced mainly in the epidermis near the basement membrane. Keratinocytes contain structural keratin and make up the bulk of the epidermis.
Bacteria have 1 cell, they reproduce asexually and create other 1 cell bacterium.
What do you need help with? This isn't really a question.