What is kwashiorkor, a protein deficiency disease, characterized by?

Correct Answer: A

Rationale: Kwashiorkor is a severe acute malnutrition condition resulting from insufficient dietary protein intake. It is characterized by symptoms such as edema, skin lesions, an enlarged liver with fatty infiltrates, and notably, muscle wasting. Muscle wasting occurs as the body breaks down muscle tissue to obtain essential amino acids for vital functions. Night blindness (option B) is associated with vitamin A deficiency, scurvy (option C) results from a lack of vitamin C, and rickets (option D) is caused by a deficiency in vitamin D, calcium, or phosphate.

Correct Answer: C

Rationale: In physics, work is defined as the transfer of energy through motion along a direction. When a force is applied to an object, and the object moves in the direction of the force, work is done on the object. The work done is calculated as the force applied multiplied by the distance the object moves in the direction of the force. Choices A and B do not fully capture the essence of work, as work is about energy transfer through motion, not merely applying force to objects at rest or in motion. Choice D is incorrect as work is not a measure of an object's potential energy; rather, it is the transfer of energy through motion.

Correct Answer: C

Rationale: Work is done on an object whenever a force causes displacement in the object's position. According to the work-energy principle, work is calculated as the force applied multiplied by the distance the object moves in the direction of the force. Therefore, work can occur whenever there is a force exerted on the object resulting in displacement, regardless of whether the object's velocity changes or it is lifted vertically. Choice A is incorrect because work can be done even without a change in velocity. Choice B is incorrect as work requires both force and displacement, not just the application of force. Choice D is incorrect because work is not limited to vertical lifting; it can happen in any direction as long as there is a force causing displacement.

Correct Answer: A

Rationale: A saturated hydrocarbon chain contains only single bonds between carbon atoms, making it 'saturated' with hydrogen atoms. Therefore, the correct answer is choice A, 'Saturated.' Choice B, 'Unsaturated,' is incorrect because it refers to hydrocarbon chains with double or triple bonds. Choice C, 'Aromatic,' is not the correct term for a hydrocarbon chain without double or triple bonds; it describes a specific type of cyclic and conjugated hydrocarbon structure. Choice D, 'Alkene,' is also incorrect as it specifically indicates a hydrocarbon chain with at least one double bond between carbon atoms.

Correct Answer: A

Rationale: Work is defined as the transfer of energy from one system to another. It is the rate at which energy is transferred or converted. Therefore, work is the rate of energy transfer, making option A the correct choice. Work involves the transfer or conversion of energy, but it is not the same as energy itself, nor is it the result of energy. Additionally, work does not change an object's energy from one form to another; instead, it involves the transfer of energy.