A is the correct answer! They fight infections
Relationship with the generation, eye colors etc
If the mutation gives an organism a trait that helps them survive, that mutation will get passed on to future generations. ... Genetic variation is multiple genes and traits in a population. The greater the diversity of genes in a population, the greater chance the population will survive a changing environment.
Mountain slopes have faster erosion because it is easier for fast moving bodies of water to carry down eroded material downhill, rather than across flat land.