Correct Answer: A

Rationale: In this context, 'insidious' means progressing slowly but having harmful effects. This matches the meaning of 'gradual,' making it the correct answer. 'Momentous' means significant or important, which is not the meaning conveyed by 'insidious.' 'Sudden' means abrupt or unexpected, opposite to the slow progression indicated by 'insidious.' 'Innocuous' means harmless, which is the opposite of the harmful effects associated with an insidious disease.

Correct Answer: B

Rationale: The correct answer is 'Immigrating' because it refers to people coming to live permanently in a foreign country. 'Emigrating' (Choice A) means leaving one's own country to settle permanently in another, which does not fit the context of people coming into the United States. 'Migrating' (Choice C) is a general term for moving from one place to another without emphasizing the aspect of settling in a new country. 'Emigrated' (Choice D) is the past tense of emigrate and does not convey the ongoing action of people moving to the United States.

Correct Answer: B

Rationale: The correct answer is 'B: Reason.' 'Rational' means based on reason or logic. Choice A, 'Angry,' is incorrect as it does not relate to the meaning of 'rational.' Choice C, 'Rodent,' is a completely unrelated term. Choice D, 'Proportion,' also does not capture the meaning of 'rational,' which is about being logical or reasonable.

Correct Answer: C

Rationale: The correct meaning of 'ominous' is 'threatening' or indicating something bad is about to happen. A is incorrect because 'ominous' does not signify a good omen. B is incorrect as 'ominous' does not relate to deceit. D is incorrect as 'ominous' does not mean 'full of thought.' Therefore, the most suitable interpretation of 'ominous' in the given sentence is 'Threatening.'

Correct Answer: A

Rationale: The correct answer is A, 'Raised.' In this context, 'elevated' means to be lifted or raised up. The doctor's instruction implies keeping the patient's head in an upward position. Choices B, C, and D are incorrect. 'Turned' suggests a change in direction, 'still' means without movement, and 'thrown back' implies a forceful backward motion, none of which capture the meaning of 'elevated' in this scenario.