Which of the following represents the first line of defense to an intruding pathogen?
A. Adaptive immunity
B. Antibodies
C. Innate immunity
D. T cells .
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.
Therefore, the Correct Answer is C.
More Questions on TEAS 7 Science
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Q #1: Which type of bond is responsible for the unique properties of water and plays a crucial role in the structure of DNA and proteins?
A. Hydrogen bonds.
B. Covalent bonds.
C. Ionic bonds.
D. Van der Waals forces.
Answer Explanation
The correct answer is choice A. Hydrogen bonds.
Hydrogen bonds are responsible for the unique properties of water and play a crucial role in the structure of DNA and proteins.
Hydrogen bonds are weak electrostatic attractions between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.
Choice B.
Covalent bonds is incorrect because covalent bonds are strong chemical bonds formed by the sharing of electrons between two atoms.
Choice C.
Ionic bonds is incorrect because ionic bonds are chemical bonds formed by the transfer of electrons from one atom to another, resulting in the formation of ions.
Choice D.
Van der Waals forces is incorrect because Van der Waals forces are weak intermolecular forces that arise from temporary dipoles induced in atoms or molecules.
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Q #2: In a well-designed experiment, all variables apart from the treatment should be kept constant between what?.
A. Control group and treatment group.
B. Independent variable and dependent variable.
C. Experimental group and non-experimental group.
D. High level and low level of the independent variable.
Answer Explanation
In a well-designed experiment, all variables apart from the treatment should be kept constant between the control group and treatment group.
This means researchers can correctly measure the entire effect of the treatment without interference from confounding variables.
Choice B) Independent variable and dependent variable is incorrect because these are not groups but rather variables.
The independent variable is manipulated by the experimenters while the dependent variable is measured to see if it changes as a result of the manipulation.
Choice C) Experimental group and non-experimental group is incorrect because a non-experimental group is not a term used in experimental design.
The correct term for the group that does not receive the treatment is control group.
Choice D) High level and low level of the independent variable is incorrect because these are levels of the independent variable, not groups.
In an experiment, there can be multiple levels of the independent variable, but they are applied to different groups (e.g.
control group, treatment group).
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Q #3: Which subatomic particle contributes to the positive charge of an atom?
A. Proton
B. Neutron
C. Electron
D. Nucleon
Answer Explanation
Protons contribute to the positive charge of an atom.
Protons are subatomic particles with a positive charge found in the nucleus of an atom.
Choice B is incorrect because neutrons are neutral and do not have a charge. Choice C is incorrect because electrons have a negative charge.
Choice D is incorrect because nucleons refer to both protons and neutrons, but only protons contribute to the positive charge of an atom.
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Q #4: A patient with chronic kidney disease is at risk for developing which of the following electrolyte imbalances?
A. Decrease in the concentration of calcium in the glomerulus.
B. Increase in the concentration of potassium in the blood.
C. Decrease in the concentration of sodium in the blood.
D. Increase in the concentration of magnesium in the blood.
Answer Explanation
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.
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Q #5: A patient with a history of heart failure is prescribed a medication that increases urine output to reduce fluid buildup. Which of the following statements best describes the mechanism of action of the prescribed medication?
A. Inhibits the renin-angiotensin-aldosterone system.
B. Blocks beta receptors.
C. Increases sodium and water reabsorption.
D. Enhances glomerular filtration rate.
Answer Explanation
The correct answer is choice D - Enhances glomerular filtration rate.
The medication prescribed to the patient is a diuretic, which removes water and electrolytes from the body by increasing urination 1.
This helps reduce fluid buildup in the body.
Choice A, Inhibits the renin-angiotensin-aldosterone system, is not the correct answer because it describes a different mechanism of action.
Choice B, Blocks beta receptors, is not the correct answer because it describes a different mechanism of action.
Choice C, Increases sodium and water reabsorption, is not the correct answer because it would have the opposite effect of reducing fluid buildup.
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Q #6: What is the organelle that encapsulates the contents of the cell and plays a vital role in regulating the movement of substances in and out of the cell?.
A. Ribosome
B. Nucleus
C. Mitochondria
D. Plasma membrane.
Answer Explanation
The plasma membrane is the organelle that encapsulates the contents of the cell and plays a vital role in regulating the movement of substances in and out of the cell.
It is a selectively permeable barrier that separates the internal environment of the cell from the external environment.
Choice A is incorrect because ribosomes are organelles involved in protein synthesis, not in regulating the movement of substances in and out of the cell.
Choice B is incorrect because the nucleus is an organelle that contains the cell’s genetic material, not in regulating the movement of substances in and out of the cell.
Choice C is incorrect because mitochondria are organelles involved in energy production, not in regulating the movement of substances in and out of the cell.
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Q #7: Which of the following is a consequence of increased viscosity of a fluid?
A. Particles have a decrease in mobility.
B. The fluid will have a lower density.
C. The fluid will have a higher flow rate.
D. The fluid will have a higher pressure.
Answer Explanation
The correct answer is choice A.
An increase in viscosity of a fluid results in a decrease in mobility of particles.
Viscosity is the resistance of a fluid to a change in shape or movement of neighboring portions relative to one another.
It denotes opposition to flow and may be thought of as internal friction between the molecules.
Choice B is incorrect because an increase in viscosity does not affect the density of a fluid.
Choice C is incorrect because an increase in viscosity results in a decrease, not an increase, in flow rate.
Choice D is incorrect because an increase in viscosity does not affect the pressure of a fluid.
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Q #8: Why is water sometimes called the "universal solvent"?.
A. Because water dissolves all solutes equally well.
B. Because water is a nonpolar solvent.
C. Because water is good at dissolving ions and polar molecules.
D. Because water is poor at dissolving nonpolar molecules.
Answer Explanation
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”.
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Q #9: Which process involves the fusion of male and female gametes resulting in the formation of a zygote?
A. Oogenesis.
B. Fertilization.
C. Meiosis.
D. Mitosis.
Answer Explanation
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.
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Q #10: Which type of lymphocyte is capable of killing tumor cells and infected cells without prior sensitization?.
A. Helper T cells.
B. B cells.
C. Natural killer cells.
D. Cytotoxic T cells .
Answer Explanation
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.
