ATI TEAS Science

Correct Answer: B

Rationale: The correct answer is B: Secondary structure. Secondary structure is defined by the local folds and coils in the protein's polypeptide backbone, such as alpha helices and beta sheets. This level of structure does not involve interactions between different regions of the protein (tertiary) or multiple protein subunits (quaternary). Primary structure (A) refers to the linear sequence of amino acids. Tertiary structure (C) involves the 3D arrangement of secondary structures and other elements in a single polypeptide chain. Quaternary structure (D) pertains to the arrangement of multiple polypeptide subunits in a protein complex.

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 somatic nervous system is responsible for voluntary movement of skeletal muscles. It controls conscious movements like walking, writing, or speaking. This system does not regulate automatic functions like breathing (option A), cognitive processes like thought (option B), or emotional responses like fear (option D). Therefore, the correct answer is C - Movement.

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: 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.