Nokea
What is the main function of white blood cells?
- A. Transport oxygen
- B. Fight infection
- C. Produce antibodies
- D. Regulate body temperature
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.
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Following the scientific method, which steps would be done before gathering qualitative data?
- A. Communicate with a scientific journal
- B. Define the problem
- C. Develop a hypothesis
- D. Categorize data for statistical analysis
Correct Answer: B
Rationale: In the scientific method, defining the problem is typically the initial step. Before gathering qualitative data, it is essential to clearly outline and understand the issue or question being addressed. This step helps in guiding the research process and ensures that the data collected are relevant to the problem at hand. Communicating with a scientific journal (Choice A) is not a standard step in the scientific method; it comes after the research is conducted. Developing a hypothesis (Choice C) usually follows defining the problem and precedes data collection. Categorizing data for statistical analysis (Choice D) occurs after data collection, not before gathering qualitative data.
What is the basic structural and functional unit of the kidney?
- A. Neuron
- B. Nephron
- C. Glomerulus
- D. Axon
Correct Answer: B
Rationale: The correct answer is B, Nephron. The nephron is indeed the basic structural and functional unit of the kidney. It is responsible for filtering blood, regulating electrolytes, maintaining fluid balance, and removing waste products. Choice A, Neuron, is incorrect as neurons are nerve cells, not specific to kidney function. Choice C, Glomerulus, is a component of the nephron but not the entire functional unit. Choice D, Axon, is a part of nerve cells and is not related to kidney structure or function.
Which of the following is responsible for producing antibodies?
- A. Red blood cells
- B. White blood cells
- C. Platelets
- D. Plasma
Correct Answer: B
Rationale: White blood cells are responsible for producing antibodies. Antibodies are essential components of the immune system that help the body combat infections by identifying and neutralizing harmful pathogens. Red blood cells are primarily responsible for carrying oxygen, platelets are involved in blood clotting, and plasma is the liquid component of blood that carries nutrients and hormones.
Consider the graph representing a botanist's data on root growth. What is the independent variable?
- A. Temperature
- B. Root tissue
- C. Light exposure
- D. Root length
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.
Which of the following enzymes unwinds the double-stranded DNA during replication?
- A. Helicase
- B. Ligase
- C. Nuclease
- D. Polymerase
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.