Nokea
Which of the following is a property of amphiprotic substances?
- A. React with acids only
- B. React with bases only
- C. Can act as both acids and bases
- D. Are inert in chemical reactions
Correct Answer: C
Rationale: The correct answer is C: Can act as both acids and bases. Amphiprotic substances have the ability to donate a proton (act as an acid) or accept a proton (act as a base) depending on the reaction conditions. This dual nature allows them to participate in a wide range of chemical reactions, making them versatile and important in various chemical processes. Choices A and B are incorrect because amphiprotic substances are not limited to reacting with only acids or bases; they can interact with both. Choice D is incorrect because amphiprotic substances are not inert; they actively participate in chemical reactions by donating or accepting protons.
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Which of the following is the smallest unit of matter?
- A. Molecule
- B. Atom
- C. Compound
- D. Element
Correct Answer: B
Rationale: An atom is the fundamental building block of matter, while molecules are formed by the combination of atoms.
What phenomenon explains the bending of light as it passes around an obstacle or through an aperture?
- A. Refraction
- B. Reflection
- C. Diffraction
- D. Dispersion
Correct Answer: C
Rationale: Diffraction is the phenomenon that explains the bending of light as it passes around an obstacle or through an aperture. When light encounters an obstacle or passes through an aperture, it diffracts, causing it to bend around the edges. Refraction, on the other hand, occurs when light passes from one medium to another, causing it to change direction. Reflection involves the bouncing back of light rays from a surface, and dispersion is the separation of light into its different colors. Therefore, the correct answer is C, as diffraction specifically addresses the bending of light as it interacts with obstacles or apertures, unlike the other choices that describe different optical phenomena.
Which of the following vessels is responsible for pumping oxygenated blood to the body?
- A. Right ventricle
- B. Left ventricle
- C. Pulmonary artery
- D. Aorta
Correct Answer: D
Rationale: The aorta is the correct answer because it is responsible for pumping oxygenated blood from the heart to the rest of the body. The aorta is the main artery that carries blood away from the heart and distributes it to all parts of the body, providing oxygen and nutrients to the tissues. Choices A, B, and C are incorrect. The right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery, the left ventricle pumps oxygenated blood to the body through the aorta, and the pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation.
Dysentery is an infectious disease caused by which type of microbe?
- A. Helminth
- B. Bacteria
- C. Protozoan
- D. Fungus
Correct Answer: B
Rationale: The correct answer is B: Bacteria. Dysentery is typically caused by bacterial infections, such as Shigella, Campylobacter, or Escherichia coli. While parasites and protozoa can also cause similar symptoms, bacterial infections are the most common causes of dysentery. Choice A (Helminth) is incorrect as helminths are parasitic worms that typically cause different types of infections. Choice C (Protozoan) is incorrect as some protozoa like Entamoeba histolytica can cause dysentery, but bacterial infections are more common. Choice D (Fungus) is incorrect as fungal infections do not typically cause dysentery.
Which vitamin plays a vital role in immune function?
- A. Vitamin A
- B. Vitamin B12
- C. Vitamin D
- D. Vitamin E
Correct Answer: C
Rationale: Vitamin D is the correct answer. It plays a vital role in immune function by regulating the immune system and enhancing the pathogen-fighting effects of monocytes and macrophages. Deficiency in Vitamin D has been linked to increased susceptibility to infections and autoimmune diseases, highlighting its importance in maintaining a healthy immune response. Vitamin A (Choice A) is essential for vision and skin health but is not primarily known for its role in immune function. Vitamin B12 (Choice B) is important for red blood cell formation and neurological function, not specifically immune function. Vitamin E (Choice D) acts as an antioxidant and is beneficial for skin health and cell function, but it is not primarily associated with immune system support.