When skin cells are damaged by ultraviolet radiation from the sun, they are replaced by new ones. Explain how this fact provides evidence that supports one or more parts of cell theory?

The cell theory states that:

1.  All living things are composed of cells (or cell products)

2.  The cell is the smallest unit of life

3.  Cells only arise from pre-existing cells

Explanation:

Cells removed from tissues can survive independently for short periods of time

Nothing smaller than a cell has been found to be able to live independently

Experiments by Francesco Redi and Louis Pasteur have demonstrated that cells cannot grow in sealed and sterile conditions

Movement:   Living things show movement, either externally or internally

Reproduction:   Living things produce offspring, either sexually or asexually

Sensitivity:   Living things can respond to and interact with the environment

Growth:   Living things can grow or change size / shape

Respiration:   Living things use substances from the environment to make energy

Excretion:   Living things exhibit the removal of wastes

Nutrition:   Living things exchange materials and gases with the environment