What are two ways in which tears to prevent microbial colonization?

1. By washing the eyes to dilute microbes

2. By the action of lysozyme

Explanation:

Tears are released in response to the presence of any irritants in the eyes. The tears are spread on the surface of the eyeball through blinking. In this way, tears keep on washing the surface of the eyes and prevent microbes to infect the same.

Tears also contain the enzyme lysozyme. Lysozyme is an enzyme that can digest the cell walls of some bacteria. Hence, invasion of certain bacterial species is prevented by innate immunity provided by lysozyme of tears.

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).