What is the name of the microscopic finger-like projections that increase the surface area for absorption in the small intestine?

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: C

Rationale: Ionic bonding is not considered an intermolecular force but an intramolecular force. Intermolecular forces occur between different molecules, while intramolecular forces act within a molecule. Hydrogen bonding, dipole-dipole interactions, and London dispersion forces are intermolecular forces. Hydrogen bonding involves a hydrogen atom bonded to a highly electronegative atom, dipole-dipole interactions occur between polar molecules, and London dispersion forces are temporary attractions between nonpolar molecules.

Correct Answer: C

Rationale: The force that caused the ball to stop rolling across the floor is air resistance. As the ball moves through the air, air resistance acts in the opposite direction of its motion, gradually slowing it down until it comes to a stop. In this scenario, the ball is not in contact with the floor, so the normal force from the floor does not play a role in stopping the ball. Gravitational force acts to pull objects towards the center of the Earth and would not directly stop the ball in this situation. Therefore, air resistance is the force that opposes the motion of the rolling ball and causes it to come to a stop.

Correct Answer: A

Rationale: The gravitational force from the Earth is responsible for keeping the satellite in its circular orbit. This force provides the necessary centripetal force required to maintain the circular motion of the satellite. The gravitational force acts as the centripetal force, pulling the satellite towards the center of the Earth, thereby keeping it in its circular path. Choices B, C, and D do not provide the necessary force to keep the satellite in its circular path. Thrust from the satellite's engine would change the speed or direction of the satellite, not maintain its circular path. Friction between the satellite and the atmosphere would act as a resistive force, slowing down the satellite rather than maintaining its orbit. The normal force from the Earth's surface is perpendicular to the surface and does not contribute to the circular motion of the satellite. Therefore, the correct answer is A, as the gravitational force acts as the centripetal force to keep the satellite in its circular path around the Earth.

Correct Answer: D

Rationale: The correct answer is D: Friction between the tires and the road. When a car travels along a curved road, the friction between the tires of the car and the road provides the necessary centripetal force required to keep the car moving in the curved path. This friction allows the tires to grip the road and prevent the car from sliding off the curve due to inertia or momentum. Choices A, B, and C are incorrect because gravitational force, normal force from the road, and air resistance do not play a significant role in keeping a car moving along a curved road. While these forces may have other effects on the car's motion, they are not the primary force responsible for maintaining the car's trajectory along a curve.