some insects eat nectar & an insect is a pollinating animal ->  some insects are pollinating animals that eat nectar  some birds eat nectar & a bird is a pollinating animal ->  some birds are pollinating animals that eat nectar  some insects are pollinating animals that eat nectar & some birds are pollinating animals that eat nectar ->  some pollinating animals eat nectar  a source of something emits / produces / generates / provides that something & a flower is a source of nectar ->  a flower produces nectar  a flower produces nectar & a flower is a part of a plant for attracting pollinators / producing seeds ->  a flower is a part of a plant for attracting pollinators that produces nectar  some pollinating animals eat nectar & a flower is a part of a plant for attracting pollinators that produces nectar -> nectar is used for attracting pollinators by plants