Correct Answer: A

Rationale: A) Prometaphase is the correct answer because it is the stage of mitosis where all chromosomes are attached to the spindle fibers before anaphase begins. During prometaphase, the nuclear envelope breaks down, allowing the spindle fibers to attach to the kinetochores of the chromosomes. This attachment is necessary for proper chromosome alignment and segregation during anaphase. B) Metaphase is incorrect because it is the stage where chromosomes are aligned at the metaphase plate but do not necessarily have all spindle fibers attached. C) Cyclin degradation is incorrect because it is a regulatory mechanism that controls the progression of the cell cycle but is not specifically related to ensuring all chromosomes are attached to spindle fibers. D) Sister chromatid cohesion is incorrect because it refers to the physical connection between sister chromatids that is maintained until anaphase, but it does not ensure that all chromosomes are attached to spindle fibers.

Correct Answer: A

Rationale: Delta waves are slow brain waves associated with deep sleep stages, specifically stages 3 and 4 of non-REM sleep. These waves have a frequency range of 0.5-4 Hz. Choice B (4-8 Hz) refers to theta waves, which are associated with light sleep and relaxation. Choice C (8-13 Hz) corresponds to alpha waves, present during wakeful relaxation. Choice D (13-30 Hz) represents beta waves, seen in active thinking and concentration. Therefore, the correct answer is A because it aligns with the frequency range characteristic of delta waves during deep sleep.

Correct Answer: B

Rationale: The primary function of the lymphatic system is to carry waste products away from tissues. Lymphatic vessels collect excess fluid, waste materials, and toxins from the body's tissues and transport them to the bloodstream for elimination. Choice A is incorrect because transporting oxygen and nutrients to cells is mainly the function of the circulatory system. Choice C is incorrect as regulating body temperature is primarily done by the body's thermoregulatory mechanisms. Choice D is incorrect because the production of red blood cells occurs in the bone marrow, not in the lymphatic system.

Correct Answer: B

Rationale: Work is directly proportional to displacement. In physics, work is defined as the product of the force applied to an object and the displacement of the object in the direction of the force. Therefore, work is directly proportional to displacement. Choice A is incorrect because work is dependent on both force and displacement. Choice C is incorrect because work is not inversely proportional to displacement; it is directly proportional. Choice D is incorrect because work is indeed related to displacement, as described in the definition of work in physics.

Correct Answer: C

Rationale: The correct answer is C, the stomach. The stomach is responsible for churning and mechanically breaking down food. It contains muscles that contract and relax to mix food with digestive juices, breaking it down into smaller particles. This mechanical digestion process helps prepare the food for further digestion and absorption in the small intestine. The small intestine is primarily responsible for the absorption of nutrients, not for mechanical digestion. The large intestine absorbs water and salts, and the esophagus is a muscular tube that transports food from the mouth to the stomach, not involved in churning or breaking down food.