Answer:
Arteries
Explanation:
There are three main types of blood vessels: veins, arteries, and capillaries. Arteries are the blood vessels that carry the oxygenated blood from the heart to various body parts. Veins pick the deoxygenated blood and deliver it to the heart to be oxygenated.
Arteries are the blood vessels with thick walls and no valves. Blood is pumped with higher pressure from the heart into arteries. The pulmonary artery is the only exception that carries deoxygenated blood from the right ventricle to the lungs for oxygenation.
<span>indicate a common ancestor exists between two organisms
</span>
NOT:
result from evolution in a similar environment
are features which organisms still have but no longer use
<span>develop when a mutation occurs in the DNA of an organism</span>
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.
