TEAS Practice Test Science

Correct Answer: B

Rationale: The correct answer is B: Meiosis Prophase I. Crossing over occurs during Prophase I of meiosis, specifically during the substage called pachytene. This is when homologous chromosomes pair up and exchange genetic material. This process creates genetic diversity among offspring. Choice A, Mitosis Prophase, is incorrect because crossing over does not occur during mitosis, as homologous chromosomes do not pair up in mitosis. Choice C, Meiosis Prophase II, is incorrect because crossing over only occurs during Prophase I, not Prophase II. Choice D, Interphase, is incorrect because crossing over does not occur during interphase, as it is a phase where the cell prepares for division and DNA replication occurs.

Correct Answer: B

Rationale: The correct answer is B: To transport oxygen and nutrients. The circulatory system, composed of the heart, blood vessels, and blood, primarily functions to deliver oxygen and nutrients to the body's cells and remove waste products. The heart pumps oxygen-rich blood to tissues and organs, ensuring they receive the necessary nutrients for energy production. In contrast, choices A, C, and D are incorrect. Regulating body temperature is primarily the role of the body's thermoregulatory system, fighting infection is the function of the immune system, and breaking down waste is the responsibility of the digestive system.

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 because DNA strands run antiparallel to each other, with one running 5' to 3' and the other running 3' to 5'. The antisense strand serves as a template for RNA synthesis during transcription, where RNA polymerase reads the antisense DNA strand and synthesizes an RNA molecule that is complementary to it. Choice A is incorrect because the sense strand runs 5' to 3'. Choice C is incorrect because the antisense strand is not directly involved in replication; it is mainly involved in transcription. Choice D is incorrect because the direction DNA is stored does not depend on the antisense strand.

Correct Answer: B

Rationale: The correct answer is B: Ball-and-socket joint. This joint allows for a wide range of motion due to its structure where a rounded end of one bone fits into a cup-like socket of another bone. The shoulder and hip joints are prime examples of ball-and-socket joints, enabling movements in multiple directions. A: Hinge joints, like the elbow, allow movement in one plane. C: Pivot joints, like the neck, allow rotational movement. D: Saddle joints, like the thumb, allow for various movements but not the same wide range as ball-and-socket joints.

Correct Answer: A

Rationale: The correct answer is A: Left atrium. The left atrium receives oxygenated blood from the lungs via the pulmonary veins. This oxygenated blood is then pumped into the left ventricle and circulated to the rest of the body. The right atrium receives deoxygenated blood from the body via the vena cava. Choices B, C, and D are incorrect because the right atrium receives deoxygenated blood from the body, the left ventricle pumps oxygenated blood to the body, and the right ventricle pumps deoxygenated blood to the lungs for oxygenation, respectively.