Q: Q: What process, which results because of great pressure at the center of a star, causes stars to shine? Read this paragraph and choose the correct option from the provided answers: Stars shine because of nuclear fusion. Fusion reactions in the Sun's core keep our nearest star burning. Stars are made mostly of hydrogen and helium. Both are very lightweight gases. A star contains so much hydrogen and helium that the weight of these gases is enormous. The pressure at the center of a star is great enough to heat the gases. This causes nuclear fusion reactions. Choices: - gravitational pull - electric fusion - energy fusion - nuclear fusion A:
A: nuclear fusion

Q: Q: Modern plants reflect what kind of changes that have occurred over many, many years? Read this paragraph and choose the correct option from the provided answers: The types of living plants today reflect the evolutionary past of the plant kingdom. From tiny nonvascular mosses to large flowering and fruiting trees, there are modern plants that represent each of the major evolutionary changes that occurred in this important eukaryotic kingdom. Choices: - unknown changes - tissue changes - tendency changes - evolutionary changes A:
A: evolutionary changes

Q: Q: Scientists often classify or organize different objects based on their what? Read this paragraph and choose the correct option from the provided answers: Choices: - experimental properties - behavioral traits - independent variables - physical properties A:
A: physical properties

Q: Q: Balanced chemical reactions are balanced in what? Read this paragraph and choose the correct option from the provided answers: Balanced chemical reactions are balanced in terms of moles. Choices: - atoms - molecular bonds - electrical charge - terms of moles A:
A: terms of moles