A deer eats grass, then a wolf eats the deer. Later, decomposers break down the wolf’s body. What happens to much of the wolf’s matter?

In a carbon cycle, carbon dioxide enters grass, moves to a rabbit, then reaches soil microbes after the rabbit dies. What can happen to that carbon next?

Water evaporates from a pond, forms clouds, falls as rain, and is absorbed by tree roots. What does this pathway show about water in ecosystems?

A dead fish sinks in a pond, and bacteria break it down. Later, algae use nutrients from the water. What happened to the fish’s nutrients?

Grass takes carbon from air to build sugar. A cow eats the grass and later leaves manure on a field. How can carbon in the manure reenter plants?

A fallen log decays, and a sapling grows nearby. What matter pathway best explains how the log helps the sapling?

An apple falls, rots, and its atoms enter soil, air, and organisms. What idea does this example support?

After leaves fall in a forest, fungi and bacteria break them down. Why is this important for the ecosystem?

In a sealed terrarium, dead leaves pile up because decomposers are missing. What problem would plants soon face?

A compost pile warms and shrinks as microbes break down vegetable scraps. What role are the microbes playing?

Bacteria in soil break animal remains into simpler substances that roots can absorb. What ecosystem role does this show?

Mushrooms grow on a dead tree trunk and slowly soften the wood. What are the mushrooms doing for the food web?

Earthworms eat dead leaves and leave nutrient-rich castings in soil. How do earthworms help the ecosystem?

Sunlight reaches grass, then energy moves to a rabbit and a fox. Why must new sunlight keep entering this food chain?

Carbon atoms in a forest can move from air to trees to animals many times. How is energy different from those atoms?

A squirrel eats an acorn and uses some stored chemical energy to move. What happens to much of that energy during the squirrel’s life?

Plants, insects, and birds reuse nitrogen atoms in proteins, but the food web still needs sunlight. What explains both observations?

In a lake, algae are eaten by small fish, and dead fish are decomposed by bacteria. What is recycled, and what mainly flows through?

After a grassland fire, ash adds minerals to soil while heat and light spread into the air. What difference between matter and energy is shown?

Only a small part of the energy in grass becomes fox biomass after rabbits eat the grass. Why can the ecosystem still reuse atoms from all levels?