Nokea
Which substance protects the body from ultraviolet rays?
- A. Keratin
- B. Sebum
- C. Perspiration
- D. Melanin
Correct Answer: D
Rationale: Melanin is the pigment responsible for skin color and serves as a natural defense against ultraviolet (UV) rays. When the skin is exposed to UV rays, melanin production increases to absorb and dissipate the radiation, acting as a protective mechanism. This helps prevent DNA damage, reducing the risk of skin cancer and other UV-induced skin issues. Therefore, melanin is the substance that effectively shields the body from the harmful effects of UV radiation.
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In experimental design, which group can be measured against the experimental group as a standard of comparison?
- A. Control
- B. Responding
- C. Manipulated
- D. Variable
Correct Answer: A
Rationale: The control group is a critical component in experimental design as it serves as a reference point for comparison with the experimental group. The control group does not receive the experimental treatment but is subjected to all other conditions. By comparing the outcomes of the experimental group with those of the control group, researchers can evaluate the impact and efficacy of the experimental treatment.
What type of tissue largely makes up the pharynx?
- A. Bone
- B. Muscle
- C. Nervous
- D. Cartilage
Correct Answer: B
Rationale: The pharynx is mostly composed of muscle tissue, which enables it to carry out functions like swallowing and breathing. Muscles in the pharynx contract to propel food into the esophagus during swallowing and aid in vocalization and respiration.
What distinguishes endocrine and exocrine glands from one another?
- A. The biochemistry of their secretions
- B. The presence or absence of ducts
- C. The presence or absence of nerve innervation
- D. The effect their secretions have on the target cell
Correct Answer: B
Rationale: The correct answer is B. The presence or absence of ducts is the key factor that distinguishes endocrine and exocrine glands. Endocrine glands secrete hormones directly into the bloodstream without ducts, while exocrine glands secrete substances through ducts to the external environment or onto a surface. Choice A is incorrect because both types of glands can have different biochemistries in their secretions. Choice C is incorrect because both types of glands can receive nerve innervation. Choice D is incorrect as it does not differentiate between endocrine and exocrine glands based on the effect of their secretions on target cells.
Which of the following pathways best represents the flow of blood from the human heart to organs?
- A. Blood pumped from the heart first enters arteries that then narrow to form arterioles that deliver blood to capillaries of the organs
- B. Blood pumped from the heart first enters veins that then narrow to form venules that deliver blood to arteries of the organ
- C. Blood pumped from the heart first enters arteries that then narrow to form arterioles that deliver blood to capillaries of the organs
- D. Blood pumped from the heart first enters arteries that then narrow to form veins that deliver blood to the organs
Correct Answer: C
Rationale: The correct pathway for the flow of blood from the human heart to organs involves a series of blood vessels. Blood is pumped from the heart into large arteries, which then branch into smaller arterioles. These arterioles deliver blood to capillaries located in the organs. Capillaries are essential for the exchange of nutrients, gases, and waste products between the blood and the tissues. This intricate network ensures efficient delivery of oxygen and nutrients to the organs and removal of waste products. Therefore, the correct sequence is for blood to flow from the heart, through arteries, then arterioles, and finally to capillaries in the organs for optimal exchange and organ function.
Which of the following are the major parts of the nervous system?
- A. PNS and Somatic Nervous System
- B. Autonomic Nervous System and CNS
- C. PNS and CNS
- D. Autonomic Nervous System and Somatic Nervous System
Correct Answer: C
Rationale: The nervous system comprises two major parts: the peripheral nervous system (PNS) and the central nervous system (CNS). The PNS includes nerves outside the brain and spinal cord, while the CNS consists of the brain and spinal cord. Choice C (PNS and CNS) correctly identifies the primary divisions of the nervous system, encompassing both the peripheral and central components. Therefore, the correct answer is C.