Which of the following substances has an acidic pH?
- A. Lemon juice
- B. Blood
- C. Urine
- D. Salt water
Correct Answer: A
Rationale: The correct answer is A, Lemon juice, which has an acidic pH typically around 2 due to its citric acid content. Blood, urine, and salt water are not typically acidic in nature. Blood has a slightly basic pH, urine can vary but is usually slightly acidic to neutral, and salt water is neutral to slightly alkaline. Lemon juice is a commonly known acidic substance, often used in cooking and cleaning due to its acidic properties.
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Which type of capillary is the most common and least permeable?
- A. Fenestrated capillaries
- B. Sinusoidal capillaries
- C. Continuous capillaries
- D. Discontinuous capillaries
Correct Answer: C
Rationale: The correct answer is C, continuous capillaries. Continuous capillaries are the most common and least permeable type of capillary. They are found in most tissues, including muscle and the nervous system. Continuous capillaries have a continuous endothelium without fenestrations or large gaps, which limits the movement of substances across their walls.
Choice A, fenestrated capillaries, have pores (fenestrations) in their endothelial cells, making them more permeable than continuous capillaries.
Choice B, sinusoidal capillaries, have a discontinuous endothelium with large gaps between cells, making them more permeable and allowing larger molecules and cells to pass through compared to continuous capillaries.
Choice D, discontinuous capillaries, are similar to sinusoidal capillaries with a discontinuous endothelium, allowing for enhanced permeability compared to continuous capillaries.
Four different groups of the same species of peas are grown and exposed to differing levels of sunlight, water, and fertilizer as documented in the table below. The data in the water and fertilizer columns indicate how many times the peas are watered or fertilized per week, respectively. Group 2 is the only group that withered. What is a reasonable explanation for this occurrence? Group Sunlight Water Fertilizer 1 partial sun 4 mL/hr 1 2 full sun 7 mL/hr 1 3 no sun 14 mL/hr 2 4 partial sun 3 mL/hr 2
- A. Insects gnawed away at the stem of the plant.
- B. The roots rotted due to poor drainage.
- C. The soil type had nutritional deficiencies.
- D. This species of peas does not thrive in full sunlight.
Correct Answer: D
Rationale: Group 2, the only group that withered, was exposed to full sun. This suggests that the species of peas being studied does not thrive in full sunlight, leading to its deterioration compared to the other groups with different light exposures. Choices A, B, and C are not the correct explanations for the withering of Group 2. There is no mention of insects in the stem, poor drainage, or soil nutritional deficiencies in the scenario provided. The key factor that sets Group 2 apart from the others is the full sunlight exposure, indicating that the species of peas is not suited for such conditions.
What is the pathway of deoxygenated blood in our body?
- A. From the lungs to the left ventricle
- B. From the body to the right atrium, then to the right ventricle, and finally to the lungs
- C. From the left atrium to the body
- D. From the aorta to the right atrium
Correct Answer: B
Rationale: The correct pathway of deoxygenated blood in our body involves blood returning from the body, entering the right atrium, then passing to the right ventricle, and eventually reaching the lungs for oxygenation. This sequence ensures that deoxygenated blood is pumped to the lungs, where it receives oxygen and releases carbon dioxide before circulating back to the body. Choices A, C, and D are incorrect because they do not follow the actual path of deoxygenated blood in the circulatory system.
Which chamber of the heart is the largest?
- A. Right atrium
- B. Left atrium
- C. Right ventricle
- D. Left ventricle
Correct Answer: D
Rationale: The correct answer is D, the left ventricle. The left ventricle is the largest and strongest chamber of the heart. It is responsible for pumping oxygenated blood to the entire body through the aorta, playing a crucial role in the circulatory system. Choices A, B, and C are incorrect. The right atrium receives deoxygenated blood from the body, the left atrium receives oxygenated blood from the lungs, and the right ventricle pumps deoxygenated blood to the lungs for oxygenation. However, the left ventricle is the largest chamber and performs the vital function of pumping oxygen-rich blood to the body.
What is the function of the immune system?
- A. To transport oxygen
- B. To fight infection
- C. To digest food
- D. To produce hormones
Correct Answer: B
Rationale: The correct answer is B: 'To fight infection.' The immune system's primary function is to protect the body from infections and foreign invaders by recognizing and responding to pathogens. It plays a crucial role in maintaining overall health and preventing diseases caused by harmful microorganisms. Choices A, C, and D are incorrect because the immune system is not responsible for transporting oxygen, digesting food, or producing hormones. These functions are carried out by other systems in the body, such as the respiratory system, digestive system, and endocrine system, respectively.