<em>Answer:</em>
<em>The answer for this statement is "True".</em>
<em>Explanation:</em>
<em>In the kidneys, the countercurrent mechanism involves the interaction between the flow of filtrate through the loop of Henle of the juxtamedullary nephrons (the countercurrent multiplier) and the flow of blood through the limbs of adjacent blood vessels (the countercurrent exchanger). This relationship establishes and maintains an osmotic gradient extending from the cortex through the depths of the medulla that allows the kidneys to vary urine concentration dramatically which is true.</em>
Answer:
To fulfill the people.of america
A cell membrane does not actually maintain homeostasis by itself. The term homeostasis refers to maintaining a relatively stable internal environment inside of a multi-cell organism. Since the internal environment is the interstitial fluid that is around each and every cell, then homeostasis has more to do with what is outside of a cell than what is inside of it. :)
Answer:
A lot of factors cause genetic variation in a population. The root of all genetic variation is mutations, which occur randomly.
A lot of genetic variation in fact results during meiosis, the process by which gametes (sex/reproductive cells) are formed. The 3 main ways are crossing over, independent assortment of chromosomes, and random fertilization. Crossing over occurs during Prophase I of meiosis, in which genetic material is exchanged between nonsister chromatids of homologous chromosomes. Independent assortment refers to the following: When cells divide during meiosis, homologous chromosomes are randomly distributed during anaphase I, separating and segregating independently of each other. Random fertilization is where any sperm can fertilize any egg cell. The many combinations of eggs and sperms mean variation.
Another source of genetic variation include gene flow. Gene flow is where populations have their members enter other populations (migration), influencing the gene pool of populations. This source is more controversial, however.
Random mating can also increase genetic variation.
Water moves upward through a plant through the xylem tissue. Along with water, xylem also transports dissolved minerals, and some small organic molecules. Three factors that influence the flow of sap through a plant include diffusion, transpiration and capillary action. Water transport occurs in a plant's xylem tissue.
