Blood type is a trait determined by multiple alleles, with IA and IB being co-dominant: IA codes for A blood and IB codes for B blood, while i codes for O blood and is recessive to both. If an A heterozygote individual and an O individual have a child, what is the probability that the child will have A blood?

Correct Answer: B

Rationale: If an A heterozygote (IAi) and an O individual (ii) have a child, there is a 50% chance the child will inherit the IA allele and have A blood. The A heterozygote can pass on either the IA or i allele, while the O individual can only pass on the i allele. Therefore, the possible genotypes for the child are IAi (A blood) or ii (O blood), resulting in a 50% chance of the child having A blood. Choice A (25%) is incorrect as it does not take into account the possibility of inheriting the IA allele. Choice C (75%) and Choice D (100%) are incorrect as they overestimate the probability of the child having A blood.

Correct Answer: A

Rationale: Mitosis is the correct answer. It is the process of cell division in somatic cells, leading to the formation of two identical daughter cells with the same number of chromosomes as the parent cell. Meiosis, on the other hand, is the type of cell division that occurs in sex cells, leading to the formation of gametes with half the number of chromosomes. Respiration is a completely different biological process related to energy production, and cytogenesis is not a recognized term for cell division.

Correct Answer: B

Rationale: The correct answer is B. In this experiment, the independent variable is the amount of poison because it is what is being manipulated by the researcher. The dependent variable is how quickly the rat dies, as it is the outcome that is being measured based on the different amounts of poison administered. Choice A is incorrect because the independent variable should be what is being manipulated or changed, which is the amount of poison in this case. Choice C is incorrect because whether the rat eats the poison is not being varied or controlled by the researcher. Choice D is incorrect because the cage the rat is kept in is not relevant to the relationship being studied between the amount of poison and the rat's survival time.

Correct Answer: B

Rationale: A model is a representation of a natural pattern or occurrence that is difficult or impossible to experience directly. Models are used to simplify complex systems or phenomena to aid in understanding or making predictions about them. The other options (A, C, and D) do not specifically refer to representations of natural patterns or occurrences as models do. A theory is an explanation based on observations, experiments, and reasoning. A law is a statement that describes a consistent natural phenomenon observed to occur without exception. An observation is a direct result of perceiving something using the senses, without being a representation or abstraction of a natural pattern.

Correct Answer: A

Rationale: A control is a standard used to compare the outcomes of an experiment and is crucial for determining the effect of the variables being tested. It helps isolate and measure the impact of the independent variable by providing a baseline for comparison. While variables may change, constants remain consistent, and collected data is the information obtained from the experiment. A control specifically serves as the standard for comparison in an experiment, making it the correct choice. Variables, although important, are what are being altered and tested in an experiment, constants are factors that are kept consistent throughout the experiment, and collected data is the information gathered from the experiment, none of which specifically serve as the standard for comparison.