"A gene pool consists of all genes, including all the different alleles that are present in a population. Number of times an allele occurs in a gene pool compared with the number of times other alleles occur. In genetic terms, evolution is any change in the relative frequency of alleles in a population."
Nucleic acids offer variability because they contain alternate forms of genes called alleles.
Various weighting schemes are used to prevent data from being misleading. For example, the most common weighting scheme is an average of values, but this can allow one value to be extremely low, while the rest are extremely high, and the averaging will allow the final result to look acceptable. On the other hand, some weighting systems use squares of deviations from the minimum recommended levels, which greatly increases the impact of a low value. Weighting factors may vary between teams of researchers, but are usually set depending on the history of the area and the methodology being done.

The Correct choice is " a "
Many organisms eat at multiple trophic levels.
The answer to this question is Homeostasis <span />