Which of the following enzymes unwinds the double-stranded DNA during replication?

Correct Answer: A

Rationale: Helicase is the enzyme responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This process creates the replication fork where DNA polymerase can then synthesize new DNA strands. Ligase functions to join Okazaki fragments on the lagging strand, not unwind DNA. Nuclease is involved in DNA repair by removing damaged DNA segments. Polymerase is responsible for synthesizing new DNA strands based on the existing template strands, not for unwinding the DNA.

Correct Answer: B

Rationale: The occipital lobe is primarily responsible for processing visual information. It contains the primary visual cortex, which plays a key role in interpreting visual stimuli. The frontal lobe is more associated with functions such as decision-making and problem-solving, making choice A incorrect. The parietal lobe is involved in processing sensory information but not specifically vision, making choice C incorrect. The temporal lobe is responsible for functions like memory and auditory processing, so choice D is also incorrect.

Correct Answer: D

Rationale: The correct answer is D: Artificially acquired active immunity. Vaccines work by stimulating the immune system to produce an active response, leading to the development of immunity against specific pathogens. Choice A, naturally acquired passive immunity, is incorrect as it refers to the temporary immunity passed from mother to child, not through vaccines. Choice B, artificially acquired passive immunity, is also incorrect because passive immunity involves the transfer of pre-formed antibodies, not the stimulation of the immune system by vaccines. Choice C, naturally acquired active immunity, is incorrect since it is acquired through natural exposure to pathogens, not through vaccines.

Correct Answer: B

Rationale: Hydrophobic proteins are known for their ability to repel water and are often involved in providing structural support in cells and tissues. They help maintain the structural integrity and shape of cell membranes, organelles, and other cellular components. Choice A, digestive enzymes, typically consist of hydrophilic proteins that interact with water and substrates to facilitate digestion. Choice C, carrying oxygen molecules, is a function commonly associated with specific proteins like hemoglobin. Choice D, storing energy, is usually performed by proteins like enzymes involved in energy storage and release, such as glycogen phosphorylase.

Correct Answer: C

Rationale: The independent variable is the factor that is intentionally changed or manipulated by the researcher. In this case, light exposure is the independent variable because it is being controlled and tested to observe its effect on root growth. Choices A, B, and D are not the independent variable in this scenario. Temperature, root tissue, and root length are likely dependent variables that could be influenced by the changes in light exposure.