Correct Answer: C

Rationale: The term 'invasive' refers to a procedure that involves entering the body, usually with a medical instrument or device. In the context provided, the doctor wants to try other non-invasive or less invasive options before resorting to an invasive procedure. 'Experimental' means untested or not yet proven to be effective, which aligns with the idea of exploring alternative methods before considering a more invasive approach. Choices A, B, and D are incorrect because they do not relate to the context of trying alternative procedures that are different from invasive ones.

Correct Answer: B

Rationale: The correct answer is B: 'Present but not active or visible.' Latent refers to something that is existing but not yet developed or manifest. Choice A, 'Easily seen,' is incorrect as latent implies the opposite - not easily seen. Choice C, 'Quick to react,' is incorrect as latent does not imply a quick reaction but rather a hidden or dormant state. Choice D, 'Actively growing,' is incorrect as latent suggests the opposite - not actively growing but rather inactive or concealed.

Correct Answer: B

Rationale: The correct definition of 'insidious' is 'So gradual as to not become apparent for a long time.' This term describes something that develops slowly and may not be noticed initially. Choice A, 'Immediate and obvious,' is incorrect because 'insidious' implies the opposite of being immediate. Choice C, 'Sudden and severe,' is incorrect because 'insidious' suggests a slow and subtle progression, not sudden. Choice D, 'Quick and detectable,' is incorrect because 'insidious' does not indicate something quick or easily detectable.

Correct Answer: B

Rationale: The correct answer is 'B: had known.' In this conditional sentence, the past perfect tense is required to indicate that knowing about the weather should have happened before going to the beach. 'Knew' (choice A and C) is in the simple past tense, which doesn't convey the sequence of events accurately. 'Could have known' (choice D) is incorrect as it implies a possibility of knowing in the past, but it doesn't fit the context of the sentence where the emphasis is on prior knowledge before going to the beach.

Correct Answer: A

Rationale: The word 'bilateral' means having or relating to two sides. It is often used to describe something that occurs on both sides, such as bilateral symmetry in which an object is symmetrical on two sides. Choice B, 'Straight,' does not capture the meaning of bilateral. Choice C, 'Symmetrical,' while related, does not specifically convey the idea of something pertaining to two sides. Choice D, 'On one side,' is the opposite of what bilateral means.