Correct Answer: B

Rationale: Crossing over occurs during Prophase I of meiosis. This stage is specifically associated with genetic recombination, where homologous chromosomes exchange genetic material. This process contributes to genetic diversity by creating new combinations of alleles. Choices A, C, and D are incorrect. In mitosis, crossing over does not occur as it involves the separation of replicated chromosomes. Meiosis Prophase II is focused on the reformation of nuclei and does not involve crossing over. Interphase is a stage where the cell prepares for division and is not associated with crossing over.

Correct Answer: B

Rationale: The main function of white blood cells is to fight infection, making choice B the correct answer. White blood cells are a crucial component of the immune system, working to defend the body against pathogens and foreign invaders. Choices A, C, and D are incorrect because white blood cells do not primarily transport oxygen, produce antibodies, or regulate body temperature. While some blood cells are involved in these functions, the primary role of white blood cells is to combat infections and maintain the body's immune response.

Correct Answer: B

Rationale: The rib cage plays a crucial role in protecting vital organs, specifically the lungs and heart, from external injuries. Choice A is incorrect because the rib cage does not primarily protect the digestive organs. Choice C is incorrect as the primary function of the rib cage is not to support movement, but to protect internal organs. Choice D is incorrect as regulating body temperature is not a function typically associated with the rib cage.

Correct Answer: B

Rationale: In quantitative research, numerical data is collected and analyzed. Choice B, tracking the dosage of a drug and its blood levels in the patient, involves collecting quantitative data, making it the correct method. Choices A, C, and D involve qualitative data such as narratives, physical observations, and journal notes, which do not align with the quantitative research method.

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.