Correct Answer: A

Rationale: The ankle bone is commonly known as the talus, which is a prominent bone in the human foot that forms the lower part of the ankle joint. It plays a crucial role in supporting body weight and allowing the foot to move in various directions. The terms talon and fascine are not accurate when referring to the ankle bone. Talon usually refers to the claw of a bird or animal, while fascine is a bundle of sticks used in construction or military engineering. Fascia, on the other hand, is a band of connective tissue and not a bone.

Correct Answer: A

Rationale: A synthetic drug is one that is artificially created in a laboratory setting rather than occurring naturally. The term 'man-made' accurately describes this process. Choices B, C, and D are incorrect. 'Phony' means fake or fraudulent, not specifically related to synthetic drugs. 'Atypical' means unusual or not typical, which doesn't directly relate to how synthetic drugs are made. 'Futile' means pointless or ineffective, which is not a characteristic of synthetic drugs.

Correct Answer: C

Rationale: Hypothetical is best defined as being assumed because it describes something that is based on a theory or assumption rather than solid proof or certainty. Hypothetical situations are used to explore different possibilities or outcomes without being confirmed as true or existing. Choice A, 'rigorous,' does not accurately define hypothetical, as it refers to something that is extremely thorough, accurate, or carefully done. Choice B, 'short-term,' is unrelated to the definition of hypothetical. Choice D, 'convinced,' does not capture the essence of hypothetical, which is more about assumptions and possibilities rather than being convinced of something.

Correct Answer: C

Rationale: In the context of the sentence, the word 'placebo' refers to a substance or treatment that resembles a real medical treatment but has no therapeutic effect. It is used as a standard against which the effects of the experimental drug are compared. A placebo is typically included in a control group in medical research to evaluate the actual effects of the experimental drug. Therefore, in this scenario, the placebo serves as a control to gauge the effectiveness of the experimental drug, making choice C the correct answer. Choices A, B, and D are incorrect because a placebo is not a fallback, substitute, or curative treatment in this context.

Correct Answer: D

Rationale: The abbreviation CDC stands for the Centers for Disease Control and Prevention, which is a well-known public health association in the United States. The CDC is a federal agency under the Department of Health and Human Services, responsible for protecting public health and safety by controlling and preventing disease, injury, and disability. Choices A, B, and C are incorrect as they do not accurately describe what the CDC is known for; it is not an online social network, a test for postgraduate students, or a pharmaceutical company.