ATI TEAS Science

Correct Answer: B

Rationale: The correct answer is B because in an experiment, the independent variable is the one that is manipulated by the researcher, which in this case is the amount of poison given to the rat. The dependent variable is the outcome that is being measured, which is how quickly the rat dies. By varying the amount of poison, we can observe the effect it has on the time it takes for the rat to die. Choices A, C, and D are incorrect because they incorrectly identify the independent and dependent variables or introduce irrelevant variables like whether the rat eats the poison or the cage the rat is kept in, which are not the variables being directly manipulated or measured in this experiment.

Correct Answer: A

Rationale: The correct answer is A because all types of muscle tissue share the properties of being contractile (ability to contract), excitable (responsive to stimuli), elastic (ability to return to original shape), and extensible (ability to stretch). Choice B is incorrect because voluntary is not a shared property of all muscle tissues. Choice C is incorrect because voluntary is not a shared property of all muscle tissues. Choice D is incorrect because voluntary is not a shared property of all muscle tissues.

Correct Answer: A

Rationale: The correct answer is A: DNA mutation. An alteration in the normal gene sequence is referred to as a mutation, which can result from changes in the DNA sequence. Mutations can lead to variations in genetic information. Gene migration (B) refers to the movement of genes between populations. Polygenic inheritance (C) involves the contribution of multiple genes to a trait. Incomplete dominance (D) is a genetic pattern where the phenotype of a heterozygous individual is intermediate between the two homozygous phenotypes.

Correct Answer: C

Rationale: The correct answer is C: Oxygen. Oxygen is a small, non-polar molecule that can easily move through the cell membrane by passive transport, specifically through simple diffusion. This process does not require energy input and occurs from areas of high concentration to areas of low concentration until equilibrium is reached. Complex sugars (A) are too large to pass through the membrane without assistance. Non-lipid soluble molecules (B) cannot pass through the lipid bilayer of the membrane. Molecules moving from areas of low concentration to areas of high concentration (D) require active transport, which involves the expenditure of energy.

Correct Answer: A

Rationale: The correct answer is A: The smallest amount of stimulus required for an individual to feel a sensation. The sensory threshold refers to the minimum level of stimulation needed for an individual to detect a particular sensation. This threshold varies from person to person and can be influenced by factors such as sensitivity and attention. Choice B is incorrect as it specifically relates to feeling pain, which is a different sensory experience. Choice C is incorrect as it refers to a response to a stimulus (movement) rather than the detection of sensation. Choice D is incorrect as it describes the origin of the stimulus rather than the threshold for sensation detection.