Answer:
Explanation:
Meiosis is a form of cell division that occurs in the sex cells of organisms. It ensures the reduction of a diploid cell to an haploid cell to allow for the formation of a diploid zygote after fertilization (contribution of both parents haploid sex cells to give a diploid zygote). Thus, this process is very essential and important.
The reduction is accomplished by 2 divisions after the duplication of chromosomes
- first division: separation of homologous pairs of chromosomes (this reduces the total in half)
- second division: separation of sister chromatids of a chromosome.
The rearrangement in meiosis occurs by crossing over/genetic recombination.
This is the exchange of genetic material between homologous pairs of chromosome bringing about a rearrangement and genetic variation
An example of a chromosomal abnormality that arises as a result of defects in this process is the Down Syndrome which is caused by a nondisjunction of the chromosomes 21 pair in a sex cell.
This condition produces offsprings that have some characteristic facial features, short stature etc
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<u>HOP</u><u>E</u><u> IT</u><u> </u><u>HELPS</u><u> </u><u>YOU</u>
Answer:
all the muscles.
Explanation:
The muscular system is composed of all muscles in the body. The main function of the muscles is to produce movement in different parts, voluntary or involuntary, creating equilibrium. Muscles are made of myocytes. There are three types of muscles: smooth muscle, skeletal muscle, and myocardium.
- The smooth muscle is formed by fusiform cells, mononucleated, and no transversal striations. There is a protein contraction system, but not as organized as the one of the skeletal muscle.
Smooth-muscle can be found in organs, vessels, veins, and arteries. It provides sustained contractions, slow and rhythmical, but not voluntary.
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Skeletal muscle is the most abundant muscle in vertebrates, constituting the somatic musculature. It proportionates motion to extremities and digits and is responsible for the position and posture of the individual. It is also involved in eye movements, respiration, mastication, deglutition, and phonation. It moves the tongue, the superior esophagus, and the pharynx.
The skeletal muscle is innervated by axons of the motor neurons coming from the CNS. The contraction of the skeletal muscle is voluntary and fast.
Cells composing the striated muscle are significantly long and multinucleated. They arrange in bundles, where cells are parallel to each other.
- Myocardium tissue is more similar to the striated tissue than to the smooth one. However, there are some differences between them. Cardiac cells are cylindrical and smaller, with ramifications. Cardiac cells only have one nucleus, and occasionally there can be two. Actin and myosin filaments are arranged just as the skeletal ones, and the contraction of cardiac cells is molecularly very similar to the skeletal
The DNA polymerases are enzymes that create DNA molecules by assembling nucleotides, the building blocks of DNA. These enzymes are essential to DNA replication and usually work in pairs to create two identical DNA strands from one original DNA molecule. During this process, DNA polymerase “reads” the existing DNA strands to create two new strands that match the existing ones.
Every time a cell divides, DNA polymerase is required to help duplicate the cell’s DNA, so that a copy of the original DNA molecule can be passed to each of the daughter cells. In this way, genetic information is transmitted from generation to generation.
Before replication can take place, an enzyme called helicase unwinds the DNA molecule from its tightly woven form. This opens up or “unzips” the double stranded DNA to give two single strands of DNA that can be used as templates for replication.
DNA polymerase adds new free nucleotides to the 3’ end of the newly-forming strand, elongating it in a 5’ to 3’ direction. However, DNA polymerase cannot begin the formation of this new chain on its own and can only add nucleotides to a pre-existing 3'-OH group. A primer is therefore needed, at which nucleotides can be added. Primers are usually composed of RNA and DNA bases and the first two bases are always RNA. These primers are made by another enzyme called primase.
Although the function of DNA polymerase is highly accurate, a mistake is made for about one in every billion base pairs copied. The DNA is therefore “proofread” by DNA polymerase after it has been copied so that misplaced base pairs can be corrected. This preserves the integrity of the original DNA strand that is passed onto the daughter cells.

A surface representation of human DNA polymerase β (Pol β), a central enzyme in the base excision repair (BER) pathway. Image Credit: niehs.nih.gov
Structure of DNA polymerase
The structure of DNA polymerase is highly conserved, meaning their catalytic subunits vary very little from one species to another, irrespective of how their domains are structured. This highly conserved structure usually indicates that the cellular functions they perform are crucial and irreplaceable and therefore require rigid maintenance to ensure their evolutionary advantage.
I think B is answer because Boiling point is a physical property.
