All life has a common ancestor which can be traced through different lineages. Due to the fact that any new generation comes from two parents who do not share the same features. As the number of generations increases the resemblance to previous ancestors begins to minimize. For example I have brown eyes just like my mother, however, my great great grandmother had hazel eyes.
The separation of the sister chromatids during the cell division occurs in the anaphase in mitosis and anaphase II in meiosis.
During the anaphase in mitosis, and the anaphase II of the meiosis, the chromosomes aligned at the center of the nucleus separates and the sister chromatids of the chromosomes starts moving towards the opposite poles as the spindle fibers starts contracting.
Bacteria and other small organisms within an ecosystem play an important role in maintaining homeostasis of an ecosystem while also helping to break down dead materials. These small organism play a vital role in decomposing of dead plant and animal matter that then becomes nutrients for the ecosystem in the future provide fertile soil for new plant life to grow supporting the cycle of life in an ecosystem.
<span>The brain stem is closest to the spinal cord.</span>
