Correct Answer: A

Rationale: In the context of the sentence provided, efficacy refers to the ability of counterfeit medicines to produce the intended or desired effect. Efficacy is closely related to effectiveness, which is the correct description in this context. 'Significance' (Choice B), 'Corollary' (Choice C), and 'Conclusion' (Choice D) do not accurately capture the meaning of efficacy in this context.

Correct Answer: C

Rationale: Another word for the gonads would be the testes in males and ovaries in females. The gonads are the primary reproductive organs that produce gametes (sperm in males and eggs in females) and sex hormones. The term 'testes' specifically refers to the male gonads, while 'ovaries' would refer to the female gonads. Therefore, 'testes' is the correct answer as it directly relates to the male gonads, making choices A, B, and D incorrect.

Correct Answer: B

Rationale: The word 'deferentially' means showing respect or submission to someone. Therefore, the closest synonym for 'deferentially' is 'respectfully' as it reflects the attitude and behavior of showing respect towards others. The other choices are incorrect: 'Imperfectly' means with flaws or errors, 'Competently' means having the necessary ability or skills, and 'Energetically' means with energy or enthusiasm, none of which capture the respectful connotation of 'deferentially.'

Correct Answer: D

Rationale: The correct answer is D: Flexible. Plastic is a material that can be easily molded or shaped, known for its flexibility. It can bend and stretch without breaking, making it versatile and durable. Choices A, B, and C are incorrect because plastic is not primarily associated with being mechanical, authentic, or durable, but rather with its ability to be shaped and its flexibility.

Correct Answer: D

Rationale: The word 'bellicose' means showing aggression or a willingness to fight. In the context of the sentence, it suggests that the children became argumentative or confrontational after spending too much time in the moving car. Therefore, the correct meaning is 'quarrelsome.' Choices A, B, and C are incorrect because 'bellicose' does not mean beautiful, selfless, or tolerant. It specifically refers to a combative or aggressive behavior, which aligns with 'quarrelsome.'