a. recycling of nutrients/elements/components/materials
b. carbon/nitrogen/another example of recycled nutrient/element
c. decomposers/saprotrophs break down organic matter/release «inorganic» nutrients
d. energy supplied by the sun
OR
energy cannot be recycled «so ongoing supply is needed»
OR
energy is lost from ecosystems as heat
e. energy flow along food chains/through food web/through trophic levels
f. photosynthesis/autotrophs make foods/trap energy
OR
autotrophs supply the food that supports primary consumers
g. oxygen «for aerobic respiration» released by autotrophs/photosynthesis/plants
h. carbon dioxide «for photosynthesis» released by respiration
i. populations limited by food supply/predator-prey/interactions/competition OR
populations regulated by negative feedback
OR
fewer/less of each successive trophic level «along the food chain»/OWTTE
j. supplies of water from rainfall/precipitation/rivers/water cycle