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 of the following is a mechanism that the body uses to regulate blood pH levels?
A. Increased respiration rate to remove excess CO2.
B. Decreased respiration rate to retain CO2.
C. Increased water intake to dilute the blood.
D. Decreased water intake to concentrate the blood.
Answer Explanation
The correct answer is choice A.
Increased respiration rate to remove excess CO2.
The body regulates blood pH through several mechanisms, including chemical buffers, the respiratory system, and the urinary system.
The respiratory system can adjust blood pH by changing the rate of respiration to remove or retain CO2.
When there is excess acid in the blood, the respiratory rate increases to remove more CO2, which helps to raise blood pH.
Choice B is incorrect because decreasing the respiration rate would retain CO2, which would lower blood pH.
Choice C is incorrect because increased water intake would not directly affect blood pH levels.
Choice D is incorrect because decreased water intake would not directly affect blood pH levels.
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Q #2: 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 #3: Which of the following hormones is responsible for regulating the body's metabolism and energy levels?
A. Estrogen
B. Progestin
C. Thyroxine
D. Androgen
Answer Explanation
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.
