Answer:
A sexual reproduction it is mostly send in single sel organisms
A rigid cell wall is found in plants so they can hold themselves up.
I'm not sure what the answer choices are, exactly, but looking up the question I found several other questions with answers, so I'm guessing based on those the choices would be:
1) physical barrier within population
2) extensive gene flow
3) chromosomal changes within population.
Which, in this case, the answer would most likely be 3) chromosomal changes within population.
The answer is A. When mitosis is complete, t<span>wo genetically identical daughter nuclei are produced.</span>
