Correct Answer: A

Rationale: Magnesium is another essential electrolyte in the human body, along with sodium, potassium, and calcium. Magnesium plays a crucial role in various bodily functions, including muscle and nerve function, regulating blood pressure, and supporting the immune system. Manganese (Choice B), magnetite (Choice C), and manganite (Choice D) are not electrolytes found in the human body. Manganese is a mineral but not an electrolyte, while magnetite and manganite are compounds and not essential electrolytes for bodily functions.

Correct Answer: A

Rationale: A stye is an infection that occurs at the base of an eyelash or on the eyelid. It is typically caused by a bacterial infection, leading to redness, swelling, and sometimes discomfort in the affected area. Choices B, C, and D are incorrect because a stye specifically refers to an infection of the eyelid area, not the eardrum, nostril, or scalp.

Correct Answer: A

Rationale: The correct answer is A: 'A test of brain activity.' EEG stands for Electroencephalogram, a test used to evaluate the electrical activity in the brain. It helps diagnose conditions like epilepsy, seizures, and other brain disorders. Choice B, 'A medical service,' is too broad and does not specifically refer to EEG. Choice C, 'A heartbeat monitor,' is incorrect as EEG does not monitor the heart. Choice D, 'A specialist in dentistry,' is unrelated to the abbreviation EEG.

Correct Answer: B

Rationale: Tepid bathwater refers to water that is neither too hot nor too cold, but rather lukewarm in temperature. It is a comfortable and soothing temperature for bathing or soaking. Choice A is incorrect because tepid water is not salty. Choice C is incorrect because icy water is cold, not tepid. Choice D is incorrect as half-full refers to the quantity of water, not its temperature.

Correct Answer: B

Rationale: Superfluous means unnecessary or more than what is needed. It refers to something that is excessive or redundant. Choice B, "Excessive," is the correct synonym for superfluous. Choices A, C, and D are incorrect. "Maximum" (Choice A) means the greatest possible amount, "Insipid" (Choice C) means lacking flavor or interest, and "Soggy" (Choice D) means soaked with liquid or water.