Correct Answer: A

Rationale: The medulla oblongata is the correct answer. It is responsible for controlling vital functions such as heart rate, blood pressure, and breathing. This part of the brainstem contains centers that regulate these essential autonomic functions to maintain homeostasis in the body. The pons and midbrain are also parts of the brainstem, but they are not primarily responsible for controlling these vital functions. The cerebellum, on the other hand, is involved in coordination and balance, not in regulating vital functions like heart rate, blood pressure, and breathing.

Correct Answer: D

Rationale: The van't Hoff factor (i) represents the number of particles a solute dissociates into in solution. For a compound that dissociates completely in water, i would be more than 1 because it breaks apart into more particles than the original compound. This is due to complete dissociation leading to an increase in the number of particles in solution, resulting in i being greater than 1. Choice A is incorrect as a compound that dissociates completely will not have an i value of 0. Choice B is incorrect because when a compound dissociates completely, the van't Hoff factor is not less than 1. Choice C is incorrect as a compound that dissociates completely will not have an i value of 1, but rather more than 1 due to the increased number of particles in solution.

Correct Answer: C

Rationale: Synergistic muscles are groups of muscles that work together in a coordinated manner to produce a specific movement. They synchronize their actions to achieve a common goal efficiently. In contrast, antagonistic muscles work in opposing directions, and agonistic muscles, also known as prime movers, are responsible for initiating a movement. Flexors and extensors represent muscles that perform contrasting actions around a joint, such as bending and straightening. Therefore, the correct answer is C - 'Synergistic muscles,' as they collaborate to facilitate a specific movement, unlike the other choices which describe different muscle functions within the body.

Correct Answer: B

Rationale: The Golgi apparatus plays a crucial role in the cell by packaging and modifying proteins and lipids synthesized by the endoplasmic reticulum. These proteins and lipids are then transported to their final destinations within the cell or outside of it. The Golgi apparatus does not break down and recycle cellular waste, generate energy through cellular respiration, or translate DNA into proteins. Its primary function is related to processing and sorting molecules for cellular use.

Correct Answer: C

Rationale: Refraction is the change in direction of light as it moves from one medium to another, such as air to water or glass. This change occurs due to variations in the speed of light in each medium, causing the light rays to bend. When light passes through different mediums, it changes its path, a phenomenon known as refraction. Choice A, Diffraction, refers to the bending of waves around obstacles and the spreading of waves when passing through small openings, not the change in direction of light when moving between mediums. Choice B, Reflection, is the bouncing back of light rays from a surface into the same medium, not the change in direction when transitioning between different mediums. Choice D, Dispersion, involves the separation of light into its constituent colors based on their different wavelengths, not the change in direction of light when passing through different mediums.