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.
Oxygen & hydrogen this may be the answer
More context? Is there a pic
The brainstem controls the flow of the message between the brain and the body.
Answer:
natural selection is animals slowly adapting to its environment
an example is giraffes, giraffes with longer necks will be able to consume more food than giraffes with shorter necks as they they can reach for the leaves on trees. over time the giraffes with shorter necks become extinct and giraffes with longer necks still remain.