How does Immigration and emigration and natality rate and mortality rate affect population?

Death is the characteristic feature of the population. When an individual gets older and dies the population decreases. Therefore, death decreases population.

The birth rate is the number of children born in a year as a share of total population. Birth rates have important short and long-term effects. Essentially, a higher birth rate will increase the...

immigration

i think you mean molecular mass. and bigger molecules diffuse slower than smaller molecules because fewer molecules can fit through the membrane.