A high level of gene flow into a population increases genetic diversity in a population. A high level of gene flow out of a population decreases genetic diversity in a population. Genetic drift is the change in allele frequencies due to "sampling error" factors. Typically, genetic drift has the biggest impact on small populations.
Gene flow (or gene migration) is a mechanism of evolution (change the allele frequencies) which transfers genetic variation among populations due to migration. High level of gene flow decreases the genetic differentiation between the two populations.
Genetic drift is a mechanism of evolution that acts by chance (“sampling error”) often when a population is reduced in size by a natural disaster (bottleneck effect) or when a small group leaves the main population and forms a colony (founder effect).
The process is called homeostasis.
Earth is the only one you can live on
I think the scientist distinguish whether an entity is living or non living be describing the single unit of life, the live cell that could multiply, reproduce and generate trough time also through ages. I hope you are satisfied with my answer and feel free to ask for more