Answer:
The correct answer is option 4. Parasympathetic division.
Explanation:
The parasympathetic division is one of the three divisions of the ANS or autonomic nervous system. It also helps in the rest system or digest system as it saves energy by slowing the heart pace by slowing the rate of contraction. This is performed with the help of nerve fibers that send signals.
Parasympathetic nerve division increases the intestinal and activity gland. This nerve division helps in relaxing the sphincter muscle in the GI tract.
Thus, the correct answer is option D.
Answer:
Genes coding for proteins involved in chiasma formation.
Explanation:
Chiasma is the connecting link between two non sister chromatids from homologous chromosomes. At chiasma chromosomal crossover takes place in which the genetic material is exchanged between the chromatids. During meiosis aneuploidy occurs if chiasma is absent or impaired due to a mutation in genes encoding for proteins involved in chiasma formation.
Aneuploidy is characterised by presence of abnormal number of chromosomes in cells. They can be 45 or 47 in number apart from the usual 46. Due to impaired chiasma, chromosome pair fails to separate and is passed on to the egg or sperm as it is hence there is one gamete with an extra chromosome and one gamete with a less chromosome. Aneuploidy can result in many genetic disorders like three copies of chromosome 21 can result in Down syndrome.
Answer:
A.
Explanation:
increasing salinity decreases solubility of gas in water, therefore dissolved O2 concentration decreases.
<span>Cells control cell division in order to maintain normal cell function. If something happens to the control of the cell division, the healthy cells will divide uncontrollably. These new cells are cancer cells. </span>
The mutations in three genes are responsible for development of cancers:
1. Mutation in proto-oncogenes. Proto-oncogenes normally signal cells to grow and differentiate. Proto-oncogenes can become oncogenes due to mutations which result in the uncontrollable division of the cells.
2. Mutation in tumor suppressor genes. In normal cells, tumor suppressor genes suppress genes essential for cell cycle and that way they prevent uncontrollable cell division. However, after a mutation in these genes, suppression is lost and the cell may progress to cancer.
3. Mutation in stability genes. In normal cells, they have no role either in cell death or growth, but they control mutation rate. Mutation in stability genes results in situation where all genes, including proto-oncogenes and tumor suppression genes, are more frequently mutated.
Answer:
The cell cycle has two main phases, interphase and mitosis. Mitosis is the process during which one cell divides into two. Interphase is the time during which preparations for mitosis are made
Explanation:
