There are many different factors, but some are: the amount of natural resources (food, water, etc.), amount of predator/prey, and availability of shelter.
the structure is the difference between the two
I believe the answer is this:
DNA replication is called semi-conservative because half of the original double-helix appears in one daughter strand formed in replication if you need any more help then please comment and let me know ok. :)
The answer is geographic distribution