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.
What is internal and external stimulus? What is an example of each?
Answer:
A internal is situated or existing in the interior of something Example:No country should interfere in another country's internal<span>
affairsAnswer:
A external stimulus </span><span>
is a detectable change in the internal or </span>
external environment. Example: When a person sees a burger when hungry they s<span>
tomach starts to growl</span>
Answer:
The correct answer is option B. The contraction forces of the innervated muscle fibers.
Explanation:
Electromyography or EMG is the study of muscle activity with the help of analyzing electric signals that are burst or generated by the contraction of the muscle fibers. In other words, it is the electrical activity of the skeletal muscles in response to a nerve's stimulation of the muscle.
EMG uses the myoelectric signals to analyze muscle that is generated during the contraction forces of the inverted muscle fibers of the skeletal muscle.
Thus, the correct answer is option B. The contraction forces of the innervated muscle fibers.
Answer:
C. facilitates the absorption of vitamin B12.
Explanation:
The Intrinsic factor is a substance that is produced by the stomach and it has the important function of producing vitamin B12 which is necessary for life. Vitamin B12 is used in the production of mature red blood cells. It also improves the function of the nervous system. The production of this intrinsic factor is a very vital role of the stomach because, in the absence of a stomach, for example, in the case of a gastrectomy, a person can only survive if he is given injections of Vitamin B12.
The stomach also serves as a holding center for food and eventually delivers the food to the small intestine and the duodenum.
