Answer:
Explanation:
Natural selection is process of differential survival and reproduction of the organisms which have better phenotypic traits over the other members of the same species. These traits help the organism to survive in unfavorable conditions and they are passed from the parents to the offsprings and through successive generations of the species.
For example, the development of long neck of the giraffe helped them to grab leaves from tree tops.
The right answer is B.
Nitrogen fixation is done by decomposers that are prokaryotes (bacteria).
<u>Take the example of legumes.
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The different species of rhizobia bacteria, which are able to infect the roots of legumes (Fabaceae family), are specific to certain host plants. Rhizobium phaseoli infects beans (Phaseolus sp).
Bacteria cause the formation of nodules on the roots by penetrating the root hairs, and transform into larger "bacteroids". The nodules are the seat of a symbiotic activity in which the plant provides the sugars and energy from photosynthesis, and in return benefits from the amino acids that are produced there.
The phospholipid bilayer is a universal component of all cell membranes. Each phospholipid molecule has a hydrophobic(water repelling) and a hydrophilic( attracted to water) end. This allows the phospholipids to arrange themselves in a way that makes a cell membrane not able to dissolve in water. The bilayer is also semi-permeable which allows only certain molecules to enter the cell.
hope this helps
