Why don't we all burn up?
Earth science

We have the atmosphere protecting us

Explanation:

There are different layers of the atmosphere that help us survive such as the ozone layer which blocks most uv rays from the sun causing us to burn less easily  

lysosome is this part of the cell is surrounded by a very thick outer membrane to protect the rest of the cell from its strong enzymes.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).