Fresh water is any body of water with a low salt concentration. Organisms in fresh water various challenges which includes; Osmotic concentration such that fresh water is permanently dilute and most cells cannot function at this concentration of ions. Varying temperatures, variation in oxygen levels and reproduction and life cycle due to permanence of habitat and physiological difficulty of regulating osmotic concentration in larvae and juveniles.
<span>This condition is called Edema. It is when something swells up, which happens when too much fluid is trapped in the soft tissues. Blood vessels emit the fluid which fills up in the soft tissue. It can happen because of burns, allergic reactions, and even pregnancy. (Sometimes women's feet swell.)</span>
<span>The main reasons why cell division is important in organisms are reproduction, repair and growth. Cell division is necessary in order for life to continue.
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The length of the cell cycle is important because it determines how quickly an organism can multiply. For single-celled organisms, this rate determines how quickly the organism can reproduce new, independent organisms. </span><span>Most of the differences in cell cycle duration between species and cells are found in the duration of specific cell cycle phases. DNA replication, for example, generally proceeds faster the simpler the organisms. One reason for this trend is simply that prokaryotic have smaller genomes and not as much DNA to be replicated.</span>
Spontaneous mutations in the bacterias DNA
