1. What is the primary role of decomposers, like bacteria and fungi, in an ecosystem?
- A. To produce food using sunlight
- B. To break down dead plants and animals
- C. To be the main food source for large animals
- D. To convert sunlight into soil
2. The idea that atoms from a dead leaf can later become part of a living tree best demonstrates which scientific principle?
- A. Energy is lost in every transfer
- B. Matter is recycled within an ecosystem
- C. New matter is created by sunlight
- D. Living things can grow without nutrients
3. A gardener adds compost, which is made of decomposed leaves and vegetable scraps, to their garden soil. What is the main purpose of this action?
- A. To add rich nutrients to the soil
- B. To make the soil a lighter color
- C. To kill any weeds growing in the garden
- D. To prevent water from evaporating
4. Which statement accurately describes one part of the matter cycle?
- A. Decomposers release nutrients from dead organisms.
- B. Plants absorb nutrients directly from dead animals without any intermediate step.
- C. The sun's energy is the primary force that breaks down complex dead matter.
- D. Matter is permanently lost from the ecosystem when an animal dies.
5. What eventually happens to the matter in a log that is left to rot on the forest floor?
- A. It is destroyed and vanishes forever.
- B. It turns into pure water.
- C. It is recycled by decomposers.
- D. It is converted directly into sunlight.
6. The movement of matter from plants to animals and then to decomposers is an example of what larger ecological concept?
- A. Energy creation
- B. Matter cycling
- C. Water evaporation
- D. Natural selection
7. What must happen to the food molecules an organism consumes before they can be used for growth?
- A. They must be converted into pure energy.
- B. They must be broken down into simpler pieces.
- C. They must be exposed to sunlight.
- D. They must be combined with water to double their size.
8. When a jaguar eats a deer, how does the matter from the deer become part of the jaguar's body?
- A. The jaguar's body directly absorbs the deer's cells and adds them to its own tissues.
- B. The deer's molecules are broken down and the resulting pieces are rearranged to build the jaguar's body.
- C. The energy from the deer is used by the jaguar to create entirely new matter from the air.
- D. The deer's matter is converted into heat, which the jaguar uses to fuel muscle growth.
9. What is the primary role of a decomposer, like a fungus growing on a fallen log, in the movement of matter?
- A. To create new energy for the ecosystem.
- B. To convert sunlight into food for animals.
- C. To provide a food source for large predators.
- D. To break down dead organisms and rearrange their molecules to build its own body, returning nutrients to the soil.
10. Which statement best describes the fundamental process that allows all organisms, from plants to animals, to grow?
- A. They convert energy directly into matter.
- B. They build their bodies by rearranging atoms and molecules from their food source.
- C. They simply add more water to their cells to increase in size.
- D. They absorb fully-formed body parts from their environment.