Conclusion this is how the nervous system in human
A variation is a reference to the differences or deviations, such as the structure and form, as for crossing over is the exchange of genetic material between the non-sister chromatids of the homologous chromosomes during meiosis.
If the membrane of a cell were no longer selectively permeable then "<span>The cell would die as it would not be able to regulate which substances could enter and leave", since a selectively permeable membrane allows both things to enter and leave for the cell's survival. </span>
Baking soda because it’s a mixture of molecules together
