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.
Since the Pitx1 gene codes for a protein crucial im lower limns development, a mutation occurring near Pitx1 gene will affect refikjs around the lower limbs but not those far away from it.
<h3>What are mutations?</h3>
Mutations refers to alterations or error that occur which change the original sequence of nucleotides in a DNA molecule.
The Pitx1 gene is a gene that codes for a protein that involved in development of the lower limbs.
A mutation near but outside of the coding region of Pitx1 may cause a loss of pelvic fins without pleiotropic effects on the pituitary gland and jaw because the pelvic fins form part of the lower limbs whole the jaws and the pituitary gland are not found in the lower limbs.
Therefore, the mutation occurring near Pitx1 gene will affect regions around the lower limbs but not those far away from it.
Learn more about mutation at: brainly.com/question/17031191
The theory of natural selection was first expounded by Charles Darwin and today it is believed to be the main process that brings about evolution.
This process is defined as the process whereby organisms who better adapt to their environment tend to survive and produce more offspring.
Hence, according to this statement, option C is correct.
More organisms are born than can survive.
Answer:
36
Explanation:
If you divide 72 by 2 the answer would be 36
