Correct Answer: B

Rationale: Endocrine glands release hormones directly into the bloodstream without the use of ducts. This allows the hormones to be distributed throughout the body to target organs or tissues. Exocrine glands, on the contrary, release their secretions through ducts to the external environment or onto a surface, such as sweat glands. Apocrine and merocrine glands are both types of exocrine glands that release their secretions through different mechanisms. Apocrine glands release their secretions along with portions of the cell itself, while merocrine glands release their secretions through exocytosis without loss of cellular material.

Correct Answer: A

Rationale: Terminal velocity in physics refers to the maximum velocity achieved by an object in free fall when the force of gravity equals the force of air resistance. At terminal velocity, the object stops accelerating and maintains a constant speed. This occurs when the opposing forces are balanced, leading to no further increase in speed. Choice B is incorrect as velocity when the object is at rest is zero, not at terminal velocity. Choice C is incorrect as instantaneous velocity refers to the velocity at a specific moment in time, not the maximum speed reached in free fall. Choice D is incorrect because terminal velocity is not exclusive to heavy objects; all objects in free fall can reach terminal velocity under the right conditions.

Correct Answer: B

Rationale: Decomposers are essential organisms in the ecosystem as they break down dead organisms and organic matter, such as bacteria, fungi, and some insects. By decomposing complex organic materials into simpler forms, they release nutrients back into the environment for other organisms to utilize. Producers (option A) are organisms that generate their own food through photosynthesis; consumers (option C) are organisms that feed on other organisms for energy, and parasites (option D) are organisms that live on or in another organism, benefiting at the host's expense rather than breaking down dead organisms for nutrient recycling.

Correct Answer: C

Rationale: The epiglottis plays a crucial role during swallowing by covering the trachea to prevent food or liquid from entering the airway, which could lead to aspiration. By acting as a lid over the trachea, it ensures that food passes down the esophagus to the stomach, preventing it from entering the lungs. Choice A is incorrect as the swallowing reflex is a coordinated muscular action involving the tongue and throat muscles. Choice B is incorrect as grinding food into smaller pieces is primarily the function of the teeth and the initial stages of digestion. Choice D is incorrect as the storage of saliva for lubrication is not a function of the epiglottis, but rather involves salivary glands.

Correct Answer: A

Rationale: The correct answer is A: Lunulae. The moon-shaped white structures at the base of fingernails are known as lunulae. They are most prominent on the thumb and are situated at the base of the nail matrix. The lunula is the visible part of the nail matrix, which is responsible for generating new nail cells. Choice B, Cuticle, is incorrect as it refers to the thin layer of skin at the base of the nail plate. Choice C, Hyponychium, is incorrect as it is the skin that lies beneath the free edge of the nail. Choice D, Matrix, is incorrect as it is the area where the nail is formed, located under the cuticle.