TEAS 7 Science Practice Test

Correct Answer: A

Rationale: The correct answer is A: calcium. Bone is primarily composed of calcium phosphate, which provides strength and rigidity to the bone structure. Calcium is crucial for bone formation and mineralization. Magnesium and potassium are important for various bodily functions but are not the primary components of bone. Collagen is a protein that provides flexibility and support but is not an inorganic material found in bones.

Correct Answer: D

Rationale: The correct answer is D because a control group is necessary in experiments to compare results with a group that does not receive the experimental treatment. In this case, if tanks A, B, or C were chosen as the control group, there would be no basis for comparison with a group that did not receive any treatment. Therefore, without a specific control group that does not undergo any experimental manipulation, it is not possible to determine the true impact of the treatment being tested. Tanks A, B, and C cannot serve as the control group in this experiment as they are all part of the experimental setup and are not kept untreated for comparison.

Correct Answer: C

Rationale: The correct answer is C (50 neutrons). Neutrons are calculated by subtracting the atomic number from the mass number. The mass number represents the total number of protons and neutrons in an atom. Since the atomic number (number of protons) is not given, we use the mass number as a total. Therefore, for an atom with a mass number of 50, it must have 50 neutrons. Choice A (38) is incorrect because it does not match the given mass number. Choice B (88) is incorrect as it is not the correct calculation based on the mass number provided. Choice D (126) is incorrect as it is not the correct calculation based on the mass number provided.

Correct Answer: A

Rationale: The correct answer is A: mRNA. mRNA (messenger RNA) contains the code for making a protein through a process called translation. mRNA is transcribed from DNA in the nucleus and carries the genetic information to the ribosomes where protein synthesis occurs. tRNA (choice B) brings amino acids to the ribosome, rRNA (choice C) is a component of the ribosome, and DNA polymerase (choice D) is involved in DNA replication, not protein synthesis.

Correct Answer: B

Rationale: The primary function of the respiratory system is to facilitate the exchange of oxygen and carbon dioxide in the body. Step 1: During inhalation, oxygen is taken into the lungs. Step 2: Oxygen is then transported to the cells via the bloodstream. Step 3: Carbon dioxide, a waste product, is removed from the body during exhalation. This process is essential for cellular respiration and energy production. Choices A, C, and D are incorrect because speech production, nutrient transport, and organ protection are not the primary functions of the respiratory system.