ati teas 7 science

Correct Answer: C

Rationale: The correct answer is C: Change in color. Chemical reactions involve the formation of new substances, which is a key characteristic. Energy is either released or absorbed during a chemical reaction, leading to changes in temperature. However, changes in color are not always indicative of a chemical reaction as it can be influenced by factors like impurities or physical changes. Therefore, C is not a reliable characteristic of a chemical reaction compared to the other choices.

Correct Answer: B

Rationale: Platelets are responsible for blood clotting, which is crucial for preventing excessive bleeding when a blood vessel is injured. They adhere to the site of injury and form a plug to stop bleeding. This function is essential for maintaining hemostasis in the body. Platelets do not carry oxygen like red blood cells (Choice A), fight infection like white blood cells (Choice C), or transport nutrients like plasma (Choice D).

Correct Answer: A

Rationale: Diastole is the correct answer because it specifically refers to the relaxation phase of the heart muscle. During diastole, the heart fills with blood before contracting in systole. Systole is the contraction phase, not relaxation. Asystole is the absence of heart contractions, not relaxation. Cardiastole is not a recognized term in relation to the heart's relaxation. Therefore, diastole is the most appropriate term for describing the relaxation of the heart muscle.

Correct Answer: D

Rationale: The main function of the lungs is to exchange oxygen and carbon dioxide between the body and the environment. This process, known as respiration, is essential for cellular function. Step 1: Oxygen is inhaled into the lungs and diffuses into the bloodstream. Step 2: Carbon dioxide produced by cells is carried to the lungs via the bloodstream and exhaled. Choice A is incorrect as the primary function of the lungs is gas exchange, not nutrient transport. Choice B is incorrect as movement coordination is a function of the nervous system. Choice C is incorrect as waste filtration is primarily done by the kidneys and liver.

Correct Answer: A

Rationale: The correct answer is A because the atomic number represents the number of protons in the nucleus of an atom, which determines the element's identity. The mass number is the total number of protons and neutrons in the nucleus, indicating the atom's mass. The number of electrons is not directly related to either the atomic or mass number, eliminating choices B and D. Choice C is incorrect because the atomic number specifically refers to the number of protons, not neutrons. Thus, choice A is the only accurate explanation of the difference between the atomic number and the mass number.