Well there are three reasons
it drains into rivers, streams, etc. or
it seeps into soil and gather underground as ground-water
or
falls into high mountains and freeze and in the summer it will melt and flows into the rivers
bottleneck effect --- > A disease wipes out almost 90% of a population of birds, but the species adapts, and after 5 years its numbers increase dramatically.
gene flow ---> A population of rats travels on a cargo ship and mate with rats in a new region.
founder effect ---> Biologists introduce a small population of lizards on an island as part of a conservation effort.
mutation ---> A change in a DNA sequence causes a lizard to develop a darker skin color, which helps it hide from predators.
<span>The total number of genes present in a population is called the gene pool. Hope this helps </span>
Calcium deficiency disease (hypocalcemia) --- like osteoporosis, osteopenia !!
