What is the hallmark of adaptive immunity?

Formation of carboxyhemoglobin.

Carbon monoxide binds to the hemoglobin to create a molecule called carboxyhemoglobin (COHb), which interferes with the body’s ability to transport and use oxygen, especially in the brain.

Choice A is incorrect because carbon monoxide poisoning occurs when carbon monoxide builds up in your bloodstream.

Choice C is incorrect because carbon monoxide poisoning does not increase the production of red blood cells.

Choice D is incorrect because decreased pulmonary function is not a potential complication of carbon monoxide poisoning.

Granzymes.

Granzymes are a family of serine proteases that are stored in and secreted from the cytotoxic granules of cytotoxic T lymphocytes (CTL) and natural killer (NK) cells.

They work in synergy with perforin, a pore-forming toxin, to induce apoptosis in target cells.

Perforin is necessary for the delivery of granzyme B to the target cell cytosol where caspase-dependent and -independent pathways to apoptosis are activated.

Perforins (choice A) are pore-forming toxins that work in synergy with granzymes to induce apoptosis in target cells.

Cytokines (choice B) are signaling molecules that regulate immune responses but do not directly induce apoptosis in target cells.

Interferons (choice D) are a type of cytokine that play a role in immune responses but do not directly induce apoptosis in target cells.

Glycogen is the storage form of glucose in the human body.

It is a polysaccharide that is stored primarily in the liver and muscle tissue and can be broken down into glucose when the body needs energy.

Choice A is incorrect because starch is a storage form of glucose in plants, not in the human body.

Choice C is incorrect because fructose is a simple sugar, not a storage form of glucose.

Choice D is incorrect because cellulose is a structural carbohydrate found in plant cell walls, not a storage form of glucose in the human body.

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.

Viruses use the host’s replication processes to produce progeny virus particles.

Viruses are obligate intracellular parasites, meaning that they require a host cell to replicate.

They hijack the host cell’s machinery to produce new virus particles.

Choice B is incorrect because viruses do not divide inside the host cell.

Instead, they use the host cell’s machinery to produce new virus particles.

Choice C is incorrect because viruses do not have their own replication processes and rely on the host cell for replication.

Choice D is incorrect because while some viruses may destroy the host cell during replication, this is not always the case and is not the primary relationship between viruses and their host cells during replication.

Concentration of solute particles in the solution.

Osmosis is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

The concentration of solute particles in the solution is the primary factor that determines the movement of water across cell membranes in osmosis.

Hydrostatic pressure (choice A) can affect the movement of water across cell membranes but is not the primary factor responsible for osmosis.

Temperature (choice C) can affect the rate of osmosis but is not the primary factor responsible for osmosis.

Kinetic energy of liquid water molecules (choice D) can affect the rate of osmosis but is not the primary factor responsible for osmosis.

The correct answer is choice A. Orthopnea.

Orthopnea refers to a condition in which a patient experiences difficulty breathing while lying down, but their breathing improves when they sit up or stand.

Choice B, Hypoxia, is not the correct answer because it refers to a condition in which there is a lack of oxygen supply to the body’s tissues.

Choice C, Tachypnea, is not the correct answer because it refers to rapid breathing.

Choice D, Bradypnea, is not the correct answer because it refers to abnormally slow breathing.

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.

Neurons communicate with each other through both electrical and chemical signals.

The electrical signal, or action potential, runs from the cell body area to the axon terminals, through a thin fiber called axon.

Neurons also communicate with one another at junctions called synapses.

At a synapse, one neuron sends a message to a target neuron—another cell.

Most synapses are chemical; these synapses communicate using chemical messengers.

Choice A is incorrect because neurons communicate not only through electrical signals but also through chemical signals.

Choice B is incorrect because neurons communicate not only through chemical signals but also through electrical signals.

Choice D is incorrect because neurons do not communicate through mechanical signals.

Ionization is the process in which an atom loses or gains electrons to form an ion.

An ion is an atom or molecule that has a net electrical charge due to the loss or gain of one or more electrons.

Choice B is not the best answer because oxidation refers to the loss of electrons from an atom or molecule.

Choice C is not the best answer because reduction refers to the gain of electrons by an atom or molecule.

Choice D is not the best answer because isotopic decay refers to the process in which an unstable atomic nucleus loses energy by emitting radiation