ATI TEAS 7 Science

Correct Answer: D

Rationale: The correct answer is D, the independent variable. This is the variable that is intentionally changed or manipulated by the researcher in a scientific investigation to observe its effect on the dependent variable. By varying the independent variable, the researcher can determine if changes in this variable cause changes in the dependent variable. The control (B) is used as a baseline for comparison, the hypothesis (C) is a proposed explanation, and the dependent variable (A) is the variable being measured as a result of changes in the independent variable.

Correct Answer: A

Rationale: The correct answer is A: Pulmonary vein. The pulmonary vein is the only blood vessel among the choices that carries oxygenated blood from the lungs back to the heart. The pulmonary artery (B) carries deoxygenated blood from the heart to the lungs. The aorta (C) carries oxygenated blood from the heart to the rest of the body. The vena cava (D) carries deoxygenated blood from the body back to the heart. Therefore, the pulmonary vein is the only blood vessel in the list that fits the description of carrying oxygenated blood from the lungs to the heart.

Correct Answer: B

Rationale: The correct answer is B: It runs 3' to 5'. The antisense strand of DNA runs in the opposite direction to the sense strand. This is essential for complementary base pairing during transcription. The 3' to 5' direction allows RNA polymerase to synthesize RNA in the 5' to 3' direction, following the template of the antisense strand. Therefore, choice B is correct. Choices A and C are incorrect because the directionality of the antisense strand is opposite to 5' to 3' and it is used in transcription, not replication. Choice D is incorrect as DNA is stored in the cell nucleus in a double helix structure, not in a specific direction.

Correct Answer: C

Rationale: The correct answer is C, the Combined oral contraceptive pill. This method uses hormones like estrogen and progestin to prevent ovulation. Firstly, estrogen suppresses follicle-stimulating hormone (FSH) production, inhibiting follicular development. Secondly, progestin thickens cervical mucus, preventing sperm penetration. Lastly, progestin also inhibits luteinizing hormone (LH) surge, preventing ovulation. Spermicide (A) works by killing sperm but does not prevent ovulation. Barrier methods (B) like condoms and diaphragms physically block sperm from reaching the egg but do not affect ovulation. Intrauterine devices (IUDs) (D) work by preventing sperm from fertilizing the egg or by altering the uterine lining, but they do not directly prevent ovulation.

Correct Answer: A

Rationale: Failed to generate a rationale after 5 retries.