ati teas 7 science

Correct Answer: B

Rationale: The correct answer is B: In a covalent bond, the shared electrons spend more time closer to the more electronegative atom. This is because the more electronegative atom attracts the electrons more strongly, causing them to be closer to that atom. This creates a partial negative charge on the more electronegative atom and a partial positive charge on the other atom. This distribution of electron density contributes to the stability of the covalent bond. Choices A, C, and D are incorrect because: A: Are completely transferred to one atom - This describes an ionic bond, not a covalent bond. C: Remain equidistant between the two atoms - Shared electrons in a covalent bond are not equidistant but are closer to one atom. D: Do not influence the bond strength - The distribution of shared electrons significantly influences the strength and properties of a covalent bond.

Correct Answer: C

Rationale: The correct answer is C: Diffraction. Diffraction is the phenomenon that explains the bending of light waves as they pass around an obstacle or through an aperture. This occurs when light waves encounter an obstruction or opening that causes the waves to spread out and bend around the edges, leading to interference patterns. Refraction (A) is the bending of light as it passes through different mediums, not around obstacles. Reflection (B) is the bouncing back of light waves when they hit a surface. Dispersion (D) is the splitting of light into its component colors due to differences in wavelength. Therefore, based on the context of the question, diffraction is the most appropriate explanation for the bending of light in this scenario.

Correct Answer: A

Rationale: The correct answer is A: Hypothesis. In the scientific method, a scientist creates a hypothesis based on observations or research. A model can be a representation or simulation of a process or system that helps in understanding or predicting outcomes. By creating a model during the hypothesis step, the scientist can visually or conceptually test their proposed explanation or prediction. This aids in designing experiments or gathering data to test the hypothesis further. Data analysis (B) occurs after experimentation, where collected data is analyzed. Experimentation (C) involves testing the hypothesis through controlled experiments. Conclusion (D) is the final step where the scientist interprets the results.

Correct Answer: B

Rationale: Step 1: Active immunity involves the body's immune response, meaning the body produces its own antibodies after exposure to a pathogen. Step 2: Passive immunity provides immediate protection through antibodies from an external source, such as maternal antibodies or antibody injections. Step 3: The key difference lies in the origin of the antibodies - body's own immune response (active) vs. external antibodies (passive). Step 4: Choice B correctly identifies this distinction, making it the correct answer. Summary: Choices A, C, and D are incorrect as they do not accurately differentiate between active and passive immunity and provide misleading information about the duration, protection spectrum, and vaccination requirements.

Correct Answer: B

Rationale: The correct answer is B. Sunscreen protects the skin by absorbing UV rays and converting them to heat. This process prevents the UV rays from penetrating the skin and causing damage. Reflecting UV rays (A) would not be as effective as absorbing them. Blocking UV rays completely (C) is not possible with sunscreen. Stimulating melanin production (D) is not the main mechanism of how sunscreen works to protect the skin.