TEAS Practice Test Science

Correct Answer: C

Rationale: The independent variable is the one that is intentionally manipulated by the researcher. In this case, the botanist is studying root growth, so the variable that the botanist can control and manipulate is the light exposure. By changing the amount of light the roots receive, the botanist can observe how it affects root growth. Temperature (choice A) and root tissue (choice B) are not variables being manipulated in this experiment, so they are not the independent variable. Root length (choice D) is the dependent variable, as it is the outcome being measured based on the changes in the independent variable, light exposure.

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: Dendrite. Dendrites are the part of the neuron that receives signals from other neurons, allowing for communication between neurons. They contain receptors that bind to neurotransmitters released by neighboring neurons. The axon (A) is responsible for transmitting signals away from the cell body. The synapse (C) is the junction between two neurons where neurotransmitters are released. The myelin sheath (D) is a protective covering that insulates the axon and speeds up signal transmission but does not receive signals from other neurons.

Correct Answer: B

Rationale: The correct answer is B: To secrete digestive enzymes. The pancreas secretes enzymes such as amylase, lipase, and protease that aid in breaking down carbohydrates, fats, and proteins in the small intestine. This process is crucial for proper digestion and absorption of nutrients. Choice A is incorrect because the pancreas does not secrete bile, which is produced by the liver. Choice C is incorrect because the absorption of nutrients primarily occurs in the small intestine, not the pancreas. Choice D is incorrect as waste transportation is mainly handled by the intestines and kidneys, not the pancreas.

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.