Explanation:
A hydrogen bond is a common type of chemical bond in organisms. As the name suggests, this type of bond involves a hydrogen atom. The hydrogen is attracted to a strongly electronegative atom, such as oxygen, fluorine, or nitrogen of a polar covalent bond in the same or another molecule.
This gives water unique properties, such as a relatively high boiling point, high specific heat, cohesion, adhesion and density.
<span>R group (or side chain) is an organic component of amino acids that is unique to each amino acid. </span> <span>Three of the amino acids have basic side chains at neutral pH: arginine (Arg), lysine (Lys), and histidine (His). Their side chains contain nitrogen and resemble ammonia, which is a base and their pKa's are high enough that they tend to bind protons, (positive charge). Aspartic acid or aspartate (Asp) and glutamic acid or glutamate (Glu) are acidic amino acids because their side chains have carboxylic acid groups whose pKa's are low enough to lose protons, (negatively charged). The non-polar amino acids contain uncharged functional groups<span> at physiological pH and are incapable of participating in hydrogen bonding. </span></span>
The form of choose is sllt
Based on the CDC guidelines a person with a CD4+ cell count between 200-400 is regarded as being in <u>the second stage</u> of the HIV infection.
Acquired Immunodeficiency Syndrome
Acquired immunodeficiency syndrome (AIDS) is a condition caused by HIV (human immunodeficiency virus). AIDS is a chronic disorder and can become life-threatening for the infected person. The HIV viruses reproduce inside the host and while doing so they destroy the CD4+ immune cells which reduce the person's ability to fight against other diseases.
CD4+ cell count and AIDS
According to the CDC (U.S. Centers for Disease Control and Prevention), HIV infection is categorized into different stages based on the number of CD4+ cells.
- Stage 1: - CD4+ cell count is more than 500 per microlitre. There are no symptoms or AIDS-related conditions.
- Stage 2: - CD4+ cell count is more than 500 per microlitre. There are no symptoms or AIDS-related conditions.
- Stage 3: - The CD4+ cell count falls below 200 and AIDS-related symptoms and conditions are present.
Learn more about HIV infection here:
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The best answer among the choices given is option D. Both growth and reproduction is the <span>characteristic of living things that is important to the survival of a group of animals rather than an individual member of this group. These two are very important in order for the survival of all the living things on Earth. Without these things, life here on Earth will end.</span>
