ATI TEAS Practice Science Test

Correct Answer: B

Rationale: The correct answer is B (18). Ossification at the growth plate occurs during adolescence when bones undergo rapid growth and development. At around age 18, the growth plates begin to close as bone growth slows down, leading to ossification replacing cartilage. At age 5 (A), the growth plates are still actively contributing to bone growth. At age 42 (C) and 91 (D), ossification is more likely related to aging processes and repair rather than growth plate replacement.

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: A

Rationale: The correct answer is A: Artificial/active immunity. The MMR vaccine provides artificial immunity because it is a vaccine created in a laboratory rather than acquired naturally. It induces active immunity by stimulating the body to produce its antibodies against measles, mumps, and rubella. This type of immunity is long-lasting and provides protection by training the immune system to recognize and fight off these diseases in the future. Choice B (Artificial/passive) is incorrect because passive immunity involves receiving pre-formed antibodies rather than activating the immune system to produce its antibodies, which is the case with the MMR vaccine. Choice C (Natural/active) is incorrect because natural immunity is acquired through exposure to the actual disease, not through vaccination. Choice D (Natural/passive) is incorrect because natural passive immunity is passed from mother to baby through breast milk or placenta, not through vaccination.

Correct Answer: D

Rationale: The correct answer is D: Melanocyte-stimulating hormone. Melanocyte-stimulating hormone stimulates the melanocytes in the skin to produce melanin, the pigment responsible for skin color. This hormone darkens the skin by increasing melanin production. A: Follicle-stimulating hormone is involved in reproductive functions, not skin color changes. B: Growth-stimulating hormone primarily affects growth and development, not skin color. C: Thyroid-stimulating hormone regulates thyroid function, not skin color.

Correct Answer: C

Rationale: The independent variable is the factor that is intentionally changed by the researcher. In this study, the type of road salt used is the independent variable because it is what the researcher is manipulating to observe its effect on the deicing time. The researcher can control and vary the type of road salt to measure its impact on the deicing process. The other choices are not the independent variable because: A (Deicing time period) is the dependent variable, B (Road used for deicing) is not something that the researcher is intentionally changing, and D (Amount of road salt used) is a controlled variable that can be adjusted but not the main factor being manipulated.