Variation means difference in genetic makeup between individuals within a specie.
Natural Selection.
It favors the better adapted organisms.
Transport of a substance from the lumen (cavity) of an organ into one side of a cell and out the other side of the cell into the extracellular fluid is called <u>transcellular transport</u>.
The two routes of transport of substances across the epithelium of the gut are by transcellular method and paracellular method.
Transcellular transport refers to the transport of solutes across a epithelial cell layer through the cells. The best example is the movement of glucose from the intestinal lumen to the extracellular fluid by the epithelial cells. The epithelial cells use the active transport to generate the transcellular transport. Active transport refers to the transport of substances from a region of its lower concentration to a region of its higher concentration against the concentration gradient using cellular energy.
Grass often dies near roads that have been <span>salted to remove ice during the winter because the salt spread out into layer of the grass </span>cell. Then the water goes into the ice because the grass is attracted to the salty ice water. Hence, this dehydrates the plant cell by removing excess water, so it dies since it can no longer perform the proper cell function.<span> </span>
All energy Earth receives from the sun is turned into energy for other things like food and nutrients.<span />
