ati teas 7 science

Correct Answer: B

Rationale: The correct answer is B: Atom. An atom is the smallest unit of matter that retains the properties of an element. Atoms are made up of protons, neutrons, and electrons. A molecule (A) consists of two or more atoms bonded together. A compound (C) is a substance composed of two or more different elements chemically bonded. An element (D) is a pure substance made up of only one type of atom. Therefore, the smallest unit of matter is the atom.

Correct Answer: D

Rationale: The correct answer is D, the independent variable. This is the variable that is intentionally changed or manipulated by the researcher in a scientific investigation to observe its effect on the dependent variable. By varying the independent variable, the researcher can determine if changes in this variable cause changes in the dependent variable. The control (B) is used as a baseline for comparison, the hypothesis (C) is a proposed explanation, and the dependent variable (A) is the variable being measured as a result of changes in the independent variable.

Correct Answer: D

Rationale: The correct answer is D: Trachea. The trachea is the largest part of the airway. It is a tube that connects the larynx to the bronchi, allowing air to pass into and out of the lungs. The trachea is larger than the bronchi, bronchioles, and alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Bronchi are the main air passages into the lungs, branching off from the trachea. Bronchioles are smaller branches of the bronchi. Therefore, the trachea is the largest structure among the given choices, making it the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Hydrogen gas and sodium chloride (NaCl). When NaOH reacts with HCl, a neutralization reaction occurs, forming water and a salt. NaOH + HCl -> NaCl + H2O. Sodium chloride and water are the products formed in this reaction. Hydrogen gas is also produced as a byproduct. Choices B, C, and D are incorrect as they do not represent the correct products of the reaction based on the chemical equation.

Correct Answer: C

Rationale: The correct answer is C: Small intestine. The small intestine is the primary site for nutrient absorption in the digestive system due to its large surface area, specialized structures called villi, and microvilli that maximize absorption efficiency. Digestive enzymes and bile are also released in the small intestine to break down nutrients for absorption. The other choices are incorrect because the esophagus is responsible for swallowing, the large intestine mainly absorbs water and electrolytes, and the stomach primarily functions in digestion by secreting gastric juices.