Correct Answer: B

Rationale: The primary cause of acne vulgaris is clogged pores and excess oil production. Acne develops when hair follicles become clogged with oil and dead skin cells, creating an environment for bacteria to thrive, leading to inflammation and acne breakouts. While dry skin, bacterial infection alone, and vitamin deficiency can contribute to acne, they are not the main underlying cause. Therefore, the correct answer is clogged pores and excess oil production, as they form the basis for the development of acne vulgaris.

Correct Answer: C

Rationale: Nuclear fusion releases a large amount of energy in a short time by combining two light atomic nuclei to form a heavier nucleus. This process is the energy source of the sun and hydrogen bombs. Radioactivity involves the spontaneous emission of particles or energy from an unstable atomic nucleus, while nuclear fission is the splitting of a heavy atomic nucleus into two or more lighter nuclei, also releasing energy. While all the options are types of nuclear reactions, nuclear fusion is specifically known for releasing a large amount of energy rapidly, making it the correct choice in this context. Choices A and B are incorrect as they do not specifically describe the process of releasing a large amount of energy in a short time. Choice D is incorrect because not all the options listed release a large amount of energy in a short time, making it an inaccurate answer.

Correct Answer: C

Rationale: Inertia is an object's resistance to a change in its state of motion, as described by Newton's first law. This means that an object will maintain its current state, whether it is stationary or moving at a constant velocity, unless it experiences an external force. Choices A and B illustrate specific instances of inertia where objects in motion or at rest continue as such without external interference. Option D refers to the force necessary to elevate an object, which is not directly linked to the concept of inertia.

Correct Answer: C

Rationale: Syncope, also known as fainting, is a temporary loss of consciousness caused by a lack of blood flow to the brain. This can occur due to various reasons such as low blood pressure, dehydration, or sudden emotional stress. Strokes involve a disruption of blood flow to the brain resulting in brain cell damage. Epilepsy is a neurological disorder characterized by recurrent seizures. Multiple sclerosis is a chronic autoimmune disease that affects the central nervous system. In this case, the correct answer is 'Syncope' as it directly relates to the temporary loss of consciousness due to decreased blood flow to the brain, distinguishing it from the other options which involve different conditions affecting the nervous system.

Correct Answer: A

Rationale: The correct answer is A: Epiphyses. Epiphyses are cartilaginous areas found at the ends of long bones, enabling growth and bone lengthening during childhood and adolescence. The diaphysis refers to the main shaft of a long bone. The periosteum is the outer bone layer responsible for nourishment and aiding in bone repair. The medullary cavity is the central cavity within the diaphysis that contains bone marrow but is not involved in new bone tissue formation.