ATI TEAS Practice Science Test

Correct Answer: A

Rationale: The correct answer is A: Adenine. Adenine forms a complementary base pair with cytosine through hydrogen bonding in DNA. This pairing is essential for maintaining the structure and stability of the DNA double helix. Adenine and cytosine form two hydrogen bonds between them. Choices B, C, and D are incorrect because cytosine does not bind with itself (B), guanine (C), or thymine (D) in DNA. Thymine pairs with adenine, while guanine pairs with cytosine. Therefore, the correct base that binds with cytosine is adenine.

Correct Answer: B

Rationale: The purpose of an electrocardiogram (ECG) is to display the heart's rate and rhythm. It measures the electrical activity of the heart, showing how well it is functioning. By analyzing the ECG waveform, healthcare providers can assess the heart's health, detect any abnormalities, and diagnose various heart conditions. It provides crucial information about the heart's electrical impulses, such as the heart rate, rhythm, and any potential irregularities like arrhythmias. Therefore, choice B is correct. Choices A, C, and D are incorrect because an ECG does not indicate the rate of blood flow, identify a person's blood group type, or determine cell type in a blood sample.

Correct Answer: C

Rationale: The correct answer is C: Chromosome. A chromosome is a rod-shaped structure formed when a single DNA molecule and its associated proteins coil tightly before cell division. This coiling helps to compact the DNA and ensure it is evenly distributed to daughter cells during cell division. Centromere (A) is a specific region of a chromosome where sister chromatids are joined. Chromatid (B) refers to one of the two identical copies of a chromosome that are joined at the centromere. Gene (D) is a segment of DNA that carries the genetic information for a specific trait. Therefore, the correct answer is chromosome as it specifically describes the rod-shaped structure formed during cell division due to the coiling of DNA and proteins.

Correct Answer: B

Rationale: The correct answer is B: The plant left outside in normal conditions serves as the control of the experiment. This is because the control group in an experiment remains unchanged and is used as a baseline for comparison. In this case, the plant left outside in normal conditions is the control as it is not subjected to any experimental manipulation, unlike the other tropical plants in the greenhouse. By comparing the growth of the plants in the greenhouse to the plant left outside, any changes in plant height can be attributed to the varying humidity levels, thus allowing for a valid comparison. Choice A is incorrect because plant height for each tropical plant is the experimental variable being measured, not the control. Choice C is incorrect as humidity level readings in the greenhouse are part of the experimental conditions, not the control. Choice D is incorrect because the amount of time used to study plant height is not the control of the experiment; it is the duration of the study.

Correct Answer: B

Rationale: The correct answer is B because urine is formed in the kidney during the process of fluid filling the collecting duct. This is where the final concentration and composition of urine are regulated. Before reaching the collecting duct, the initial filtration of blood occurs in the glomerulus (eliminating options C) and the fluid does not become urine until it has passed through the collecting duct (eliminating options A and D). So, the correct sequence is filtration in the glomerulus, reabsorption and secretion in the tubules, and final urine formation in the collecting duct.