plants and water.

animals and gases.

 plants, animals and microorganisms. 

water and layers of gas.

Sweet grass is palatable, but lacks nutrients.

Sweet grass is unpalatable, but nutritious.

Sweet grass is unpalatable and lacks nutrients.

Sweet grass is palatable and nutritious.

the soil.

height above sea level.

long-term weather conditions.

Decomposer → Producer → Carnivore

Producer → Herbivore → Carnivore

Herbivore → Carnivore → Producer

Carnivore → Producer → Herbivore

An ecosystem consists of the living things and non-living things around you.

An ecosystem consists of the living things around you.

An ecosystem consists of the living things and non-living things around you, as well as the interactions amongst them. 

An ecosystem consists of the non-living things around you.

Light availability

Air pressure

Tree cover

Water clarity

secondary consumers to producers.

apex predators to tertiary consumers.

producers to primary consumers.

tertiary consumers to secondary consumers.