TEAS Practice Test Science

Correct Answer: A

Rationale: The correct answer is A: Helicase. Helicase is responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This allows the DNA strands to separate and serve as templates for the synthesis of new DNA strands by DNA polymerase. Ligase is responsible for joining the DNA fragments together, nuclease is involved in DNA repair by cutting out damaged DNA, and polymerase is responsible for synthesizing new DNA strands based on the template strands. Therefore, only helicase directly unwinds the double-stranded DNA during replication.

Correct Answer: B

Rationale: The correct answer is B: White blood cells. White blood cells are a crucial component of the immune system as they play a key role in defending the body against infections and diseases. They help identify and destroy pathogens, produce antibodies, and regulate the immune response. Red blood cells (A) are responsible for transporting oxygen, platelets (C) are involved in blood clotting, and plasma (D) is the liquid component of blood, but they are not directly involved in the immune response. Therefore, white blood cells are the correct choice for being a component of the immune system.

Correct Answer: D

Rationale: Rationale: 1. Choice A is correct as the left ventricle pumps oxygen-rich blood into the aorta. 2. Choice B is correct as the right ventricle pumps deoxygenated blood into the pulmonary trunk. 3. Choice C is correct as ventricles are indeed the main pumping chambers of the heart. 4. Therefore, choice D, "All of the above," is correct as it encompasses all true statements about the ventricles. Other choices are incorrect as they do not cover all accurate statements.

Correct Answer: B

Rationale: The correct answer is B: To exchange gases. The main function of the respiratory system is to facilitate the exchange of oxygen and carbon dioxide between the body and the external environment. This process occurs in the lungs through breathing, where oxygen is taken in and carbon dioxide is expelled. Absorbing nutrients (A) is the function of the digestive system, transporting oxygen (C) is part of the circulatory system's role, and regulating blood pressure (D) is primarily controlled by the cardiovascular system.

Correct Answer: B

Rationale: The correct answer is B: Scapula. Flat bones are thin, flattened bones that provide protection and allow for muscle attachment. The scapula fits this description as it is a thin, flat bone located on the back of the shoulder. The other choices (A: Femur, C: Humerus, D: Tibia) are long bones that are not thin and flat like flat bones. The femur, humerus, and tibia are all weight-bearing bones with a different shape and function compared to flat bones.