ati teas 7 science

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: D

Rationale: The correct answer is D, both transcription and translation. First, DNA undergoes transcription to produce mRNA, which carries the genetic information. Then, during translation, mRNA is used by ribosomes to synthesize proteins. Replication (A) is the process of copying DNA, not directly related to protein synthesis. Transcription (B) is the step where DNA is transcribed into mRNA. Translation (C) is the process where mRNA is translated into proteins. Therefore, both transcription and translation are essential steps in the flow of genetic information from DNA to protein.

Correct Answer: B

Rationale: The correct answer is B because not all fungi are parasitic and harmful to humans. Some fungi are beneficial, while others are neutral. A is correct as fungi can be unicellular or multicellular. C is true as fungi are crucial in breaking down organic matter. D is accurate as some fungi, such as mushrooms, are consumed as food. Overall, choice B is false because it wrongly generalizes all fungi as harmful, which is not the case.

Correct Answer: C

Rationale: The correct answer is C (2+ or 3+). Iron is a transition metal, meaning it has variable oxidation states. Iron commonly forms cations with charges of 2+ (Fe²⁺) or 3+ (Fe³⁺) due to its ability to lose 2 or 3 electrons, respectively, from its outer shell. This is consistent with the typical behavior of transition metals to exhibit multiple oxidation states. Choices A and B are incorrect because iron does not commonly form cations with charges of 2- or 3-. Choice D is incorrect as iron typically forms cations with a positive charge, not a negative charge.

Correct Answer: A

Rationale: The correct answer is A: Hydrogen bonding. Water molecules exhibit hydrogen bonding, where the partially positive hydrogen of one water molecule is attracted to the partially negative oxygen of another water molecule. This strong intermolecular force leads to the cohesive forces that create high surface tension in water. B: London dispersion forces are weaker and do not contribute significantly to water's high surface tension. C: Ionic bonding involves the transfer of electrons between atoms, not relevant to water's surface tension. D: Metallic bonding occurs in metals and is not related to the surface tension of water.