How many neurons typically comprise a sensory pathway?

Correct Answer: C

Rationale: A sensory pathway generally consists of three neurons: a first-order neuron, a second-order neuron, and a third-order neuron. The first-order neuron carries sensory information from the periphery to the spinal cord or brainstem. The second-order neuron then transmits this information to the thalamus or cerebellum. Finally, the third-order neuron projects the sensory input to the cerebral cortex for processing and perception. Therefore, the correct answer is 3 (C). Choices A, B, and D are incorrect as they do not align with the typical structure of a sensory pathway involving three neurons.

Correct Answer: C

Rationale: The correct answer is 'C: An inference.' An inference is a conclusion reached based on evidence and reasoning. In this statement, the conclusion that someone must have forgotten to water the flower is drawn from the evidence that the flower is dead. Choice A, 'A classification,' is incorrect because the statement does not involve categorizing or grouping. Choice B, 'An observation,' is incorrect as the statement goes beyond just stating a fact and makes a conclusion. Choice D, 'A collection,' is unrelated to the process of drawing a conclusion based on the given evidence.

Correct Answer: D

Rationale: The correct answer is D. Gametes are the reproductive cells produced by meiosis. Meiosis is the cell division process that results in the formation of gametes, which are sperm cells in males and egg cells in females. Genes (A), alleles (B), and chromatids (C) are not the reproductive cells produced by meiosis. Genes are units of heredity, alleles are different forms of a gene, and chromatids are duplicated chromosomes involved in cell division.

Correct Answer: A

Rationale: The sensory threshold refers to the smallest amount of stimulus required for an individual to perceive or feel a sensation. It is the minimum level of stimulus intensity that is detectable by an individual. Choice B is incorrect because the sensory threshold is not specifically related to feeling pain but rather to perceiving any sensation. Choice C is incorrect as the sensory threshold is about perception and not necessarily physical reaction. Choice D is incorrect as it describes the source of the stimulus, not the threshold for perception.

Correct Answer: D

Rationale: The correct answer is D: Arteries. Arteries are blood vessels that carry oxygen-rich blood away from the heart to supply oxygen to the tissues and organs throughout the body. Veins, choice A, carry oxygen-poor blood back to the heart, not oxygen-rich blood. Intestines, choice B, are part of the digestive system and do not play a role in carrying blood. Bronchioles, choice C, are small air passages in the lungs responsible for carrying air, not 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: C

Rationale: Visual processing begins in the retina, not the cornea, optic nerve, or eyelid. The retina is a layer of tissue at the back of the eye that contains photoreceptor cells responsible for converting light into neural signals that are then sent to the brain for processing. The cornea is the transparent outer layer of the eye that helps focus light, but it does not process visual information. The optic nerve transmits visual information from the retina to the brain, it does not initiate visual processing. The eyelid is a protective covering for the eye and is not involved in visual processing.

Correct Answer: D

Rationale: The correct answer is 'D: Catabolism.' Catabolism specifically involves breaking down large molecules into smaller ones to release energy. It is the opposite of anabolism, which is the process of building larger molecules from smaller ones. 'Metabolism' (choice A) is a broader term that encompasses all chemical processes in an organism, including anabolism and catabolism. 'Bioenergetics' (choice B) refers to the flow and transformation of energy in a biological system, not specifically the breakdown of molecules for energy.

Correct Answer: A

Rationale: A DNA mutation is the correct term used to describe an alteration in the normal gene sequence. It refers to changes in the DNA sequence that can result in different traits or characteristics. Gene migration involves the movement of genes between populations, polygenic inheritance refers to the inheritance of traits controlled by multiple genes, and incomplete dominance is a pattern of inheritance where neither allele is dominant.