What are the four nucleotide bases found in DNA?

The correct answer is choice A.

The superior vena cava is the largest vein in the human body that returns deoxygenated blood from the upper half of the body to the right atrium of the heart.

Choice B is incorrect because the inferior vena cava returns deoxygenated blood from the lower half of the body to the right atrium of the heart.

Choice C is incorrect because the pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart.

Choice D is incorrect because the renal vein carries deoxygenated blood from the kidneys to the inferior vena cava.

Natural killer cells.

Natural killer (NK) cells are large granular lymphocytes that are capable of destroying cells infected by viruses or bacteria and susceptible tumor cells without prior sensitization and restriction by MHC antigens.

Helper T cells (choice A) are a type of white blood cell that helps other immune cells respond to infections but do not directly kill infected or tumor cells.

B cells (choice B) are a type of white blood cell that produces antibodies to fight infections but do not directly kill infected or tumor cells.

Cytotoxic T cells (choice D) are a type of white blood cell that can kill infected or tumor cells but require prior sensitization to do so.

Inflammatory cytokines released during the early response to bacterial infection play a crucial role in initiating cell recruitment and local inflammation 1.

They induce the expression of adhesion molecules in endothelial cells and promote the recruitment of neutrophils to the site of inflammation 1.

Choice A is incorrect because while inflammatory cytokines may enhance phagocytosis, they do not directly disrupt the infection.

Choice B is incorrect because inflammatory cytokines do not directly attack invading pathogens.

Choice D is incorrect because inflammatory cytokines do not secrete antibodies to neutralize pathogens.

Fertilization.

Fertilization is the process by which male and female gametes fuse to form a zygote.

Oogenesis (choice A) is the process by which female gametes, or eggs, are produced.

Meiosis (choice C) is a type of cell division that results in the formation of gametes.

Mitosis (choice D) is a type of cell division that results in the formation of two identical daughter cells.

The correct answer is choice A.

The spleen is an organ in the human body that is responsible for the removal of damaged red blood cells and the production of certain types of white blood cells.

Choice B is incorrect because the kidneys are responsible for filtering waste from the blood and regulating electrolyte balance.

Choice C is incorrect because the pancreas produces hormones and enzymes that aid in digestion.

Choice D is incorrect because the thyroid gland produces hormones that regulate metabolism.

Water is sometimes called the “universal solvent” because it dissolves more substances than any other liquid.

This is due to its polarity and ability to form hydrogen bonds, which allows it to dissolve ions and polar molecules.

Choice A) Because water dissolves all solutes equally well is incorrect because water does not dissolve all solutes equally well.

Choice B) Because water is a nonpolar solvent is incorrect because water is a polar solvent.

Choice D) Because water is poor at dissolving nonpolar molecules is incorrect because it does not explain why water is called the “universal solvent”.

The correct answer is choice B.

A patient with chronic kidney disease is at risk for developing an increase in the concentration of potassium in the blood.

The kidneys play a pivotal role in the regulation of electrolyte balance.

With progressive loss of kidney function, derangements in electrolytes inevitably occur and contribute to poor patient outcomes123.

Choice A is incorrect because calcium concentration is not regulated in the glomerulus.

Choice C is incorrect because chronic kidney disease can result in either an increase or decrease in sodium concentration in the blood.

Choice D is incorrect because chronic kidney disease does not necessarily result in an increase in magnesium concentration in the blood.

The correct answer is choice C. Thyroxine.

Thyroxine (T4) is a hormone produced by the thyroid gland that controls your body’s metabolism, the process in which your body transforms the food you eat into energy.

Choice A, Estrogen, is not the correct answer because it is a hormone responsible for the development of female secondary sexual characteristics.

Choice B, Progestin, is not the correct answer because it is a synthetic form of progesterone used in hormonal birth control and hormone replacement therapy.

Choice D, Androgen, is not the correct answer because it is a hormone responsible for the development of male secondary sexual characteristics.

Innate immunity represents the first line of defense to an intruding pathogen.

The innate immune system is a series of nonspecific defenses that make up the innate immune system.

These defenses are not directed against any one pathogen but instead provide a guard against all infection.

Choice A is incorrect because adaptive immunity is activated when pathogens are able to bypass innate immune defenses.

Choice B is incorrect because antibodies are part of the adaptive immune system and are produced by B cells.

Choice D is incorrect because T cells are part of the adaptive immune system and assist B cells or directly kill infected cells.

Atomic mass is very close to mass number but with some deviation in the decimal places.

Atomic mass is also known as atomic weight and is the weighted average mass of an atom of an element based on the relative natural abundance of that element’s isotopes.

The mass number, on the other hand, is a count of the total number of protons and neutrons in an atom’s nucleus.

Choice A is incorrect because atomic mass and mass number do not mean the same thing.

Choice B is incorrect because atomic mass is not always greater than mass number.

Choice C is incorrect because atomic mass and mass number are related.