Answer:
Mutations and sexual reproduction increase genetic variation in a population. Natural selection occurs when environmental pressures favor certain traits that are passed on to offspring. ... Individuals may mutate, but natural selection acts by shifting the characteristics of the population as a whole.
Explanation:
Answer:
Ribosomes are found 'free' in the cytoplasm or bound to the endoplasmic reticulum (ER) to form rough ER.
Explanation:
In a mammalian cell there can be as many as 10 million ribosomes. Several ribosomes can be attached to the same mRNA strand, this structure is called a polysome.
<span>A major volcanic belt known as the ring of fire circles the Pacific Ocean. The Pacific Ring of Fire </span><span>is an area where a large number of earthquakes and volcanic eruptions occur in the basin of the </span>Pacific<span> Ocean.</span>
Bacteria is important because this bacteria binds hydrogen molecules with the gaseous nitrogen to form ammonia in the soil. During assimilation, or when plants take up nitrates from the soil, bacteria aid in the process with the plants in making ammonia. Animal wastes is also a major place where bacteria thrives and produces ammonia. The process in which assimilation occurs in plants, and then bacteria converts the nitrates to ammonia is called ammonification. From the conversion of ammonia to nitrites, bacteria also aids in this process called nitrification. The nitrifying bacteria mostly present in soils, oxidize ammonia into nitrites, and from nitrites to nitrates.
Finally, the process of denitrification also has bacteria present to aid in converting nitrates back into a gaseous form of nitrogen in the atmosphere.
