Answer:
The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.
Therefore, B is the answer.
"All living cells require water for survival" is NOT a statement from the cell theory.
A protective layer that shields the surface from lethal ultraviolet light is found in the layer of the atmosphere known as the Stratosphere.
Therefore, the correct answer is option C for this specific statement.<span />
The statement " Each gene in the human genome codes for a single protein. "is just wrong, as according to the basic knowledge of human genome, o<span>nly about 2 percent of the genome codes for proteins. This answer does make difference and clearly explaines why the previous one is wrong. Hope you will find it helpful!</span>