Cell specialization is essential to an organism because cell specialization is what allows cells to provide the essential functions of life for an organism that have a wide variety of functions and purposes. Cell specialization leads to the diversity of cells in an organism such as the human body that build and allow essential organs and bodily functions to occur. Cell specialization is an essential building block that allows multi-celled and complex organisms to move and function.
They are formed primarily on the cell's Ribosomes.
Answer:
a. two plant species flowering at different times.
Explanation:
<em>The only option that is not a post-zygotic reproductive isolation mechanism would be option a, when two plant species flower at different times.</em>
Post-zygotic reproductive isolation mechanisms are those mechanisms that act to ensure that the product of fertilization remains invalid. This is as opposed to pre-zygotic isolation mechanisms that act to prevent fertilization and hence, formation of zygotes.
In option b, c, d and e; the zygote has been formed already and all the forces are just acting to ensure that it remains invalid. whereas in option a, there is no fertilization yet.
<u>Two plant species flowering at different times will ensure that there is no cross pollination between the two species. Without pollination, there cannot be a zygote formation.</u>
Hence, the correct option is a.
<span>The connections between cells become weakened, and the leaves break off with time. Many trees and shrubs lose their leaves when they are still very colorful. Some plants retain a great deal of their foliage through much of the winter, but the leaves do not retain their color for long.</span>
