Correct Answer: B

Rationale: The correct answer is the vas deferens. It is the muscular tube responsible for carrying sperm from the testes to the urethra. After sperm is produced in the testes, it moves to the epididymis for maturation and storage. The seminal vesicle contributes fluid to semen, but it is not the tube that transports sperm. Cowper's gland also adds fluid to semen but is not involved in transporting sperm. Therefore, the vas deferens is the accurate choice for the muscular tube that transports sperm.

Correct Answer: B

Rationale: The shimmering image of water seen on a hot road is a result of refraction, not reflection. Refraction is the bending of light as it passes from one medium to another of different optical density. In this case, the hot air just above the road has a different density than the cooler air above it, causing light to bend and create the illusion of water on the road. Refraction is the most suitable explanation for this phenomenon, as it involves the bending of light rays due to the change in the medium's optical density, producing the visual effect observed on the hot road. Reflection, interference, and polarization do not involve the bending of light due to changes in optical density and are not applicable to the scenario described on the hot road.

Correct Answer: C

Rationale: A) Goblet cells: Goblet cells are specialized cells that secrete mucus to protect the lining of the digestive tract. While important for maintaining the health of the intestines, goblet cells do not increase the surface area for absorption in the small intestine. B) Paneth cells: Paneth cells are specialized cells found in the small intestine that secrete antimicrobial peptides. They play a role in protecting the intestinal stem cells and maintaining the gut microbiota balance, but they do not increase the surface area for absorption. C) Villi: Villi are microscopic finger-like projections found in the small intestine that increase the surface area available for absorption of nutrients. Each villus contains blood vessels and lacteals (lymphatic vessels) that help absorb nutrients from digested food. D) Crypts of Lieberk¼hn: Crypts of Lieberk¼hn are small pits located between the villi

Correct Answer: B

Rationale: Hyperthyroidism is a condition where the thyroid gland is overactive and produces an excessive amount of thyroid hormones. This can lead to symptoms such as weight loss, rapid heartbeat, sweating, and nervousness. Diabetes mellitus is a condition characterized by high blood sugar levels due to either insufficient insulin production or the body's inability to respond to insulin. Hypothyroidism is the opposite of hyperthyroidism, where the thyroid gland is underactive and produces insufficient thyroid hormones. Cushing's syndrome is a disorder that occurs when the body has a high level of the hormone cortisol for a long time.

Correct Answer: B

Rationale: K-strategists are species with a low reproductive rate that invest more resources in raising fewer offspring. These species typically live in stable environments with limited resources. The main factor limiting population growth in K-strategists is the availability of resources such as food, shelter, and space. When resources are scarce, K-strategists may struggle to find enough to support their population size, leading to reduced reproductive success and population growth. While predation, competition, and disease can also impact population growth, the primary limiting factor for K-strategists is the availability of resources.