Every species exhibits variations based on various genes being activated at various times. An example with humans can be eye color or hair color. What species means is that all members of a species can procreate with healthy, capable of procreating progeny, but anything else is just a variation.
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.