Answer:
Plants and animals benefit each other as members of food chains and ecosystems. For instance, flowering plants rely on bees and hummingbirds to pollinate them, while animals eat plants and sometimes make homes in them. When animals die and decompose, they enrich the soil with nitrates that stimulate plant growth. I know it's not 5, but I hope it helped.
The R group varies, and it is the carbon-phosphate backbone
