ATI TEAS Science Practice Test

Correct Answer: C

Rationale: Option C provides the most thorough experimental design by including a control group. In the first round, varying sugar intake levels help explore the relationship between sugar consumption and test scores. In the second round, by having participants consume no sugar, the student can compare results to observe any changes due to sugar intake. This approach enhances the validity of the findings by accounting for potential confounding factors and better identifying causal relationships. Choice A is not ideal as it lacks a control group and does not compare the impact of sugar consumption. Choice B does not explore the effects of sugar consumption adequately as it does not include a group without sugar. Choice D does not allow for comparison between different sugar consumption levels, limiting the ability to draw meaningful conclusions.

Correct Answer: A

Rationale: The correct answer is 'Myelin.' Myelin is a fatty substance that functions as an insulator for axons, providing protection and enhancing the speed of electrical impulses along neurons. This insulation is essential for ensuring efficient and rapid communication within the nervous system. Choices B, C, and D are incorrect. Dendrites are branched extensions of a neuron that receive signals, neurons are the basic building blocks of the nervous system that transmit information, and synapses are the junctions between neurons where communication occurs.

Correct Answer: B

Rationale: The tricuspid valve (right atrioventricular valve) prevents backflow into the right atrium when the right ventricle contracts. This valve ensures that blood flows in the correct direction, preventing regurgitation into the atrium. The pulmonary valve is responsible for preventing backflow into the right ventricle from the pulmonary artery. The mitral valve prevents backflow into the left atrium, and the aortic valve prevents backflow into the left ventricle from the aorta. Therefore, the correct answer is the tricuspid valve as it specifically addresses the scenario of backflow into the atrium during ventricular contraction.

Correct Answer: C

Rationale: The microprocessor, a key component of modern computers, played a crucial role in the success of the Human Genome Project. The ability of microprocessors to process vast amounts of data quickly and efficiently allowed scientists to analyze the massive amounts of genetic information generated by the project. This technological advancement significantly accelerated the pace of genome sequencing and data analysis, ultimately leading to the completion of the project ahead of schedule. Choices A, B, and D are incorrect. The sonogram is used for imaging in medical diagnostics, X-ray diffraction is a technique for studying the structure of materials at the atomic level, and Magnetic Resonance Imaging (MRI) is a medical imaging technique that uses magnetic fields and radio waves to produce detailed images of the body. While these inventions have their own importance in various fields, they did not have the same impact on the Human Genome Project as the microprocessor did.

Correct Answer: B

Rationale: To prepare 250 mL of a 50 M solution of HCl, the formula V1 x C1 = V2 x C2 is used, where V1 is the volume of the stock solution, C1 is the concentration of the stock solution, V2 is the final volume of the desired solution, and C2 is the final concentration of the desired solution. Given V1 x 0 M = 250 mL x 50 M, solving for V1 results in V1 = (250 mL x 50 M) / 0 M = 32 mL. Therefore, 32 mL of the 0 M stock solution of HCl needs to be added to water to create a 250 mL solution of 50 M HCl. Choices A, C, and D are incorrect because they do not represent the accurate volume required for the dilution calculation based on the given concentrations and volumes in the problem.