The correct answer is that it is an organism's habitat and inherited traits that determine its niche.
The principle of competitive exclusion states that the two species cannot hold the similar niche in the same habitat. A niche of an organism is predicted by its habitat that is its physical surrounding. The inherited traits and adaptation enhances the organism's chances of survival, and it also predicts a niche of an organism.
The answer is A, a vaccine. This is why they are often given to children for prevention.
Asexual organisms produce clones of themselves. That leaves the organism prone to being wiped out in its entirety, because every individual is equally in trouble when danger strikes. A virus or predator that affects one affects them all. It has no possibility of exploring new places, new foods, new methods of escape.
Souce: https://www.quora.com/Why-dont-all-organisms-reproduce-asexually
They both use a reproductive strategy called alternation of generations, where there are two different reproducing morphologies: a diploid sporophyte, and a haplod gametophyte. The sporophyte produces spores by meiosis (2N -> N), which disperse and form the gametophyte, which produces gametes by mitosis (N ->N). Two of those gametes fuse to create a diplod zygote (N + N -> 2N), which becomes the new sporophyte
There are differences between the two types of plants, especially the relative size of the sporophytes and gametophytes, but they both use this kind of reproductive strategy.
