ATI TEAS 7 Science

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: C

Rationale: The correct answer is C: Polypeptide. Translation is the process in which mRNA is decoded by ribosomes to synthesize a specific polypeptide. During translation, transfer RNA (tRNA) molecules bring specific amino acids to the ribosome based on the mRNA codons, and these amino acids are joined together to form a polypeptide chain. The other choices are incorrect because translation does not result in the production of DNA (A), lipids (B), or carbohydrates (D). Translation specifically involves the synthesis of polypeptides, making choice C the correct answer.

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: C

Rationale: The primary function of the lymphatic system is to fight infection and remove excess fluid. Lymph nodes contain white blood cells that help fight pathogens. Lymphatic vessels collect excess fluid from tissues and transport it back to the bloodstream, aiding in immune response. Other choices are incorrect because A: Oxygen transport is primarily done by the circulatory system, B: Blood filtration is mainly carried out by the kidneys, and D: Hormone transport is primarily through the circulatory system.

Correct Answer: D

Rationale: The correct answer is D because all the options are valid obstacles to achieving controlled nuclear fusion on Earth. Lack of suitable materials (A) is crucial due to extreme conditions, limited fusion fuels (B) can hinder sustained reactions, and containing plasma (C) is challenging to prevent energy loss. Therefore, all factors must be addressed for successful fusion energy production.