ati teas 7 science

Correct Answer: C

Rationale: The Law of Conservation of Energy states that energy cannot be created or destroyed, only transferred or transformed within a closed system. Therefore, the total amount of energy in a closed system remains constant over time. This is because energy is conserved and does not disappear or appear out of nowhere. The other choices are incorrect because energy does not increase (choice A) or decrease (choice B) in a closed system unless energy is coming in or going out of the system. The total energy in a closed system is independent of the temperature of the system (choice D) and is solely determined by the initial energy within the system and any energy transfers or transformations that occur within it.

Correct Answer: A

Rationale: The correct answer is A: Atom. An atom is the smallest unit of an element that retains its chemical properties. Atoms are composed of protons, neutrons, and electrons. Molecules (B) are made up of two or more atoms bonded together. Compounds (C) are substances composed of two or more different elements chemically bonded. Mixtures (D) are combinations of two or more substances that are physically mixed but not chemically bonded. Therefore, in this context, the correct answer is atom as it specifically refers to the smallest amount of an element that can exist independently with its unique chemical properties.

Correct Answer: C

Rationale: Step 1: Amphiprotic substances can donate and accept protons, making them capable of acting as both acids and bases. Step 2: When amphiprotic substances react, they can donate or accept protons depending on the reaction conditions. Step 3: This ability allows them to exhibit properties of both acids and bases. Step 4: Therefore, Choice C is correct as it accurately describes the nature of amphiprotic substances. Summary: A: Incorrect - Amphiprotic substances can react with both acids and bases, not just acids. B: Incorrect - Amphiprotic substances can react with both acids and bases, not just bases. D: Incorrect - Amphiprotic substances are not inert; they actively participate in chemical reactions by donating and accepting protons.

Correct Answer: A

Rationale: The correct answer is A: Meters per second. The speed of light in a vacuum is a measure of how fast light travels, which is approximately 299,792,458 meters per second. This unit is commonly used in physics to quantify the speed of light. Hertz (B) is a unit of frequency, Candela (C) is a unit of luminous intensity, and Newton (D) is a unit of force, not speed. Therefore, A is the correct unit to measure the speed of light in a vacuum.

Correct Answer: B

Rationale: The correct answer is B: Cerebrospinal fluid. This is the protective fluid that surrounds the brain and spinal cord. It acts as a cushion, providing mechanical protection, and helps to maintain a stable environment for the central nervous system. Blood (A) does not directly surround the brain and spinal cord. Myelin sheath (C) is a protective covering of nerve fibers, not the fluid surrounding the brain and spinal cord. Insulin (D) is a hormone involved in regulating blood sugar levels and is not the fluid that protects the brain and spinal cord.