Correct Answer: D

Rationale: The correct answer is D, 'All of the above.' Saltatory conduction is faster than normal nerve conduction, occurs from one node of Ranvier to the next, and is exclusive to myelinated neurons. This form of conduction allows for the rapid transmission of nerve impulses by the action potential jumping between the nodes of Ranvier in myelinated neurons, enhancing the efficiency of signal propagation along the axon. Choice A is correct as saltatory conduction is indeed faster than normal conduction. Choice B is accurate as it describes the mechanism of conduction 'jumping' from one node of Ranvier to the next. Choice C is correct because saltatory conduction occurs specifically in myelinated neurons where the myelin sheath insulates the axon except at the nodes of Ranvier, facilitating faster transmission of nerve impulses.

Correct Answer: A

Rationale: The correct answer is A: Pulmonary vein. The pulmonary vein carries oxygenated blood from the lungs to the heart. It is essential to distinguish between the pulmonary vein (A) and the pulmonary artery (B) in this context. The pulmonary vein transports oxygenated blood, while the pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation. The aorta (C) functions as the main artery that delivers oxygenated blood from the heart to the body's tissues, while the vena cava (D) returns deoxygenated blood from the body to the heart.

Correct Answer: B

Rationale: The correct answer is B, cytoplasm. Cytoplasm is the fluid-filled, jelly-like substance within the cell that suspends the organelles. The nucleus, not the correct answer, is the organelle that contains the cell's genetic material. The plasma membrane, another incorrect choice, is the outer boundary of the cell that regulates what enters and exits the cell. The Golgi apparatus, also an incorrect choice, is an organelle involved in processing and packaging proteins.

Correct Answer: D

Rationale: The correct answer is D because water's polarity enables it to dissolve a wide variety of substances, making it a versatile solvent. This property is due to water's ability to form hydrogen bonds with other molecules, allowing it to break them apart and surround the solute particles, facilitating dissolution. Choices A, B, and C are incorrect as water having a neutral pH, a high specific heat capacity, and polar covalent bonds are also true properties of water. However, the most relevant property related to its versatility as a solvent is its dissolving capability.

Correct Answer: A

Rationale: Acceleration is defined as the rate of change of velocity of an object over time. It represents how an object's velocity is changing, either by speeding up, slowing down, or changing direction. Option B, 'Speed in a straight line,' actually refers to velocity, not acceleration. Option C, 'Distance covered in a given time,' is more related to speed, as it measures how much ground is covered in a specific time period. Option D, 'Force applied to an object,' is not the definition of acceleration; it is a force exerted on an object that can cause acceleration.