The obvious answer is a bc it does not use and toxic fuels
Answer:
1 . The stage on the first meiotic division when the homologous chromosomes move to opposite poles but the sister chromatids remain together
: b. Anaphase I
2 . The stage in the second meiotic division where sister chromatids migrate to opposite poles
: c. Anaphase II
3 . A structure on the chromosome that holds a pair of chromatids together during replication
: f. centromere
4 . A double-stranded chromosome following replication attached by a centromere
: d. chromatid
5 . A condition where non-sister chromatid of homologous chromosomes exchange genes
: e. crossing over
6 . The stage in the first meiotic division where the homologous chromosomes line up as a pair
: a. Metaphase I
7 . The stage in the second meiotic division where the chromatid pair lines up at the equator of the cell: g. Metaphase II
Explanation:
DNA replication occurs during the S phase of the interphase of the cell cycle. The replicated DNA molecules are accommodated in two sister chromatids of a chromosome that are held together by a centromere.
During prophase I, the chromatids of a homologous chromosome pair exchange a genetic segment. This process is called crossing over. It generates recombinant chromatids with new combinations of genes.
Metaphase I of meiosis I includes the alignment of homologous pairs of chromosomes at the cell's equator. This is followed by separation and movement of homologous chromosomes to the opposite poles of the cell during anaphase I.
Metaphase II of meiosis II includes the alignment of individual chromosomes, each with two sister chromatids, on the cell's equator. During anaphase II, splitting centromere separates the sister chromatids which then move to the opposite poles of the cell.
Natural selection is the process that result in the adaptation of an organism to environment by means of selectively reproducing changes in its genotype, or genetic constitution. It is the a key mechanism of evolution. Charles Darwin popularised the term "natural selection" contrasting it with artificial selection, which is intentional, whereas natural selection is not.
To make it simple, let's have a group of beetle composing of green and some are brown as an example. here, there is a variation in traits. Since the environment could not support continuous population growth, not all species can reproduce to their full potential. Green beetles can easily be eaten by other species like birds compared to brown beetles. The surviving brown beetles will then generate brown offsprings because their trait has a genetic basis. Since more brown beetles survive and becomes more common in the population, the process continues until all individuals will eventually be brown. so basically, if you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome.
