Correct Answer: C

Rationale: The small intestine is the primary site of nutrient absorption in the digestive system. It is where the majority of digestion and absorption of nutrients such as carbohydrates, proteins, and fats occurs. The inner lining of the small intestine is covered in tiny finger-like projections called villi, which increase the surface area available for absorption. Nutrients are absorbed through the walls of the small intestine and into the bloodstream to be transported to cells throughout the body. The stomach's main role is to break down food through the action of stomach acids and enzymes but does not absorb nutrients. The large intestine primarily absorbs water and electrolytes from the remaining indigestible food matter, and the esophagus is a muscular tube that transports food from the mouth to the stomach, without being involved in nutrient absorption.

Correct Answer: A

Rationale: Kinetic energy is the form of energy associated with the motion of an object. When an object is in motion, it possesses kinetic energy due to its movement. Potential energy, on the other hand, is stored energy that an object has due to its position or condition. Thermal energy is related to heat, while electrical energy is associated with the flow of electric charge. In this case, the correct answer is kinetic energy as it directly correlates with the motion of an object.

Correct Answer: D

Rationale: The production of antibodies specific to a particular pathogen is a function of the adaptive immune response, not the innate immune response. Innate immunity involves nonspecific defense mechanisms like physical barriers, phagocytes, and inflammation, which provide immediate protection against pathogens without prior exposure. Antibody production is a characteristic of adaptive immunity, where the body generates specific antibodies in response to encountering a pathogen for the first time. Therefore, option D is the correct answer as it does not align with the immediate and nonspecific nature of the innate immune response.

Correct Answer: B

Rationale: Smooth muscle is the correct answer. It is found in the walls of hollow organs like the stomach and intestines, where it performs involuntary contractions to move substances through these organs. Cardiac muscle, found in the heart, is responsible for pumping blood. Skeletal muscle is attached to bones and involved in voluntary movements. Striated muscle is a term often used interchangeably with skeletal muscle, which is responsible for voluntary movements but not typically found in the walls of hollow organs like the stomach and intestines.

Correct Answer: B

Rationale: Weight is the property of matter that refers to the force of gravity acting on an object. Mass is the amount of matter in an object, not affected by gravity. Density is the mass per unit volume of a substance, not directly related to gravity. Volume is the amount of space that an object occupies, not a measure of gravity's force.