ati teas 7 science

Correct Answer: C

Rationale: The correct answer is C because lifting a box to place it on a shelf involves exerting a force to overcome gravity, resulting in the displacement of the box. Work is defined as the product of force and displacement in the direction of the force applied. In this scenario, the force applied (lifting the box) results in the box being displaced vertically, which meets the criteria for work being done. Choices A, B, and D do not represent work being done on an object because in these situations, the objects do not experience a displacement in the direction of the force applied. In choice A, the wall does not move, so no displacement occurs. In choice B, carrying a heavy object without lifting it does not involve any vertical displacement. In choice D, holding a book stationary in your hand does not result in any displacement of the book. Therefore, only choice C fulfills the criteria for work being done on an object.

Correct Answer: C

Rationale: The correct answer is C: Emulsify fats. Bile helps emulsify fats by breaking them down into smaller droplets, increasing the surface area for enzymes to digest fats. This aids in the absorption of fats and fat-soluble vitamins in the small intestine. Choice A is incorrect because bile does not break down carbohydrates. Choice B is incorrect as bile does not break down proteins. Choice D is incorrect because bile does not neutralize stomach acid; rather, it helps with fat digestion in the small intestine.

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: Remodeling. Bone remodeling is the process of breaking down and rebuilding bone tissue to maintain bone strength and repair micro-damage. It involves osteoclasts breaking down old bone and osteoblasts forming new bone. Ossification (A) is the process of bone formation. Calcification (C) is the deposition of calcium salts in tissues. Osteoporosis (D) is a condition characterized by weakened bones due to loss of bone density, not the process of breaking down and rebuilding bone tissue.

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.