What are groups of cells that perform the same function called?
- A. tissues
- B. plastids
- C. organs
- D. molecules
Correct Answer: A
Rationale: Groups of cells that perform the same function are called tissues. Tissues are composed of a group of similar cells working together to carry out specific functions within an organism. Each type of tissue has a specialized structure that enables it to perform its specific role effectively. Plastids are cell organelles found in plants responsible for functions like photosynthesis and storage, not groups of cells. Organs are composed of different types of tissues working together. Molecules are made up of atoms and are not groups of cells.
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Which organ system is most responsible for maintaining control of body temperature?
- A. The skeletal system.
- B. The circulatory system.
- C. The immune system.
- D. The muscular system.
Correct Answer: B
Rationale: The circulatory system is the correct answer as it plays a crucial role in maintaining control of body temperature through a process called thermoregulation. Blood vessels near the skin surface dilate to dissipate heat when the body is too warm and constrict to reduce heat loss when it's too cold. Additionally, the circulatory system helps distribute heat produced from metabolic processes throughout the body to keep a stable internal temperature. The skeletal system provides structural support, the immune system defends against pathogens, and the muscular system is responsible for movement, but they are not primarily involved in regulating body temperature.
In the human skeleton, which of the following lists some of the vertebrae in descending order?
- A. Atlas, axis, thoracic, lumbar, sacral, coccyx.
- B. Axis, sacral, coccyx, atlas, lumbar, thoracic.
- C. Thoracic, sacral, lumbar, axis, coccyx, atlas.
- D. Coccyx, lumbar, axis, sacral, thoracic, atlas.
Correct Answer: A
Rationale: The correct order of some of the vertebrae in the human skeleton in descending order is Atlas, Axis, Thoracic, Lumbar, Sacral, Coccyx. This sequence follows the typical arrangement from the top of the spine down towards the pelvis. Choice B is incorrect as it does not follow the descending order of vertebrae. Choice C is incorrect as it starts with Thoracic which is not the first vertebra in the descending order. Choice D is incorrect as it starts with Coccyx which is the last vertebra in the descending order.
What causes varicose veins to occur?
- A. Atherosclerosis.
- B. Incompetent valves.
- C. Loss of skin turgor.
- D. Loss of blood vessel elasticity.
Correct Answer: B
Rationale: Varicose veins occur when the valves within the veins become incompetent, leading to blood pooling in the veins instead of being efficiently pumped back to the heart. This causes the veins to become enlarged, twisted, and visible under the skin. Factors such as genetics, aging, pregnancy, and prolonged standing or sitting can contribute to the development of incompetent valves and the resulting varicose veins. Atherosclerosis is the buildup of plaque in arteries, not veins, and does not directly cause varicose veins. Loss of skin turgor is related to skin elasticity and not a direct cause of varicose veins. Loss of blood vessel elasticity is a general term and does not specifically address the mechanism behind varicose veins, which is primarily due to incompetent valves.
Which class of hormones is most likely to be released after a serious injury?
- A. Acetylcholine
- B. Oxytocin
- C. Luteinizing hormone
- D. Endorphins
Correct Answer: D
Rationale: Endorphins are the class of hormones most likely to be released after a serious injury. Endorphins are the body's natural pain relievers and are produced in response to stress or pain, helping to alleviate discomfort and promote a sense of well-being. Acetylcholine is a neurotransmitter, not a hormone. Oxytocin is mainly involved in childbirth and lactation. Luteinizing hormone is involved in reproductive functions such as ovulation. Therefore, choices A, B, and C are incorrect in the context of a hormone release following a serious injury.
Which of the following items is NOT a primary function of a healthy immune system?
- A. The immune system helps the body avoid infections.
- B. The immune system detects infections.
- C. The immune system eliminates infections.
- D. The immune system creates infections.
Correct Answer: D
Rationale: The correct answer is D. The primary functions of a healthy immune system do not involve creating infections. A healthy immune system helps the body avoid infections by providing defense mechanisms, detects infections by recognizing harmful pathogens, and eliminates infections by attacking and clearing out pathogens. Creating infections goes against the protective role of the immune system and is not a function it performs. Therefore, choices A, B, and C are correct functions of a healthy immune system, while choice D is incorrect.