ati teas 7 science

Correct Answer: B

Rationale: The correct answer is B: 2H2 + O2 → 2H2O. This equation is balanced because there are equal numbers of each type of atom on both sides of the equation. Balancing involves adjusting the coefficients to ensure the conservation of mass. In this case, there are 2 hydrogen atoms on each side and 2 oxygen atoms on each side, making it balanced. Explanation for other choices: A: H2 + O2 → H2O - Not balanced, as there are 2 hydrogen atoms on the left but only 1 on the right. C: 3H2O → 2H2 + O2 - Not balanced, as there are 6 hydrogen atoms on the left but only 2 on the right. D: H2O → H2 + O2 - Not balanced, as there are 1 oxygen atom on the left but 2 on the right.

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.

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: Vitamin D. When the skin is exposed to sunlight, a form of cholesterol in the skin is converted into Vitamin D. This vitamin plays a crucial role in calcium absorption and bone health. Vitamin A is not synthesized in the skin but obtained through diet. Vitamin C is obtained from fruits and vegetables. Vitamin E is a fat-soluble vitamin found in nuts and seeds. In summary, only Vitamin D is synthesized in the skin upon sunlight exposure, making it the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Myosin. Myosin is the protein complex responsible for the thick filament in the sarcomere. It forms cross-bridges with actin during muscle contraction. Actin (choice A) is the thin filament in the sarcomere. Tropomyosin (choice C) is a regulatory protein that covers the myosin-binding sites on actin when the muscle is at rest. Troponin (choice D) is another regulatory protein that helps regulate muscle contraction by binding calcium ions.