I would say immigration only.
emigration would theoretically reduce the genetic variation as unique individuals leave, but immigration would bring unique traits into circulation in an ecosystem.
I'm not super great at biogy tho so this might not be right... :)
They occur in germ cell DNA, which are the cells that create sperm or Ova. For every 85 million nucleotides assembled in DNA during human sperm or Ova production, One will be a mutation
I think its strain or sprained
The answer is letter A. In most organisms cellular respiration usually involves oxygen to produce the most energy. Except in the process of fermentation, where the cells are deprived with oxygen causing it to form bacteria and other forms of organisms within the fermented sample.