Science Flashcards

What is the primary source of energy for life on Earth?

Answer: The Sun

The Sun is the fundamental source of nearly all energy on Earth. It powers photosynthesis in plants, which forms the base of most food chains, and its energy drives weather patterns, creating wind and contributing to the formation of fossil fuels over geological time.

Which of the following is an example of a chemical change?

Answer: A nail rusting

A chemical change results in the formation of new substances with different chemical properties. Rusting is a classic example where iron reacts with oxygen and moisture to form iron oxide (rust), a completely new compound. In contrast, melting, boiling, and breaking are physical changes that alter appearance but not chemical composition.

What do plants release into the atmosphere during photosynthesis?

Answer: Oxygen

During photosynthesis, plants use sunlight, water, and carbon dioxide to create glucose (sugar) for energy. A vital byproduct of this process is oxygen, which is released into the atmosphere. This oxygen is essential for the respiration of most living organisms on Earth.

Which layer of Earth is made up of solid rock and forms the continents and ocean floors?

Answer: Crust

The Earth's crust is the outermost and thinnest layer of our planet, composed of solid rock. It forms both the continents, which are thicker and less dense, and the ocean floors, which are thinner and denser. The mantle and core are deeper layers with different compositions and characteristics.

What is the main function of the roots in a plant?

Answer: To anchor the plant and absorb water and nutrients from the soil

Plant roots perform two crucial functions for the plant's survival. They anchor the plant firmly in the soil, providing stability against wind and other forces. Additionally, their extensive network absorbs water and essential mineral nutrients from the soil, which are then transported to the rest of the plant.