A group of similar classes forms a phylum. The classification of organisms helps in the their study. A club is the thickened end of a butterfly's antenna . Many reptiles are ectothermic. The two animals are called commensals.
Commensalism is a type of symbiosis .
These organisms interact and influence each others survival. An optic nerve then carries this information to the insect's brain. A consumer is a living thing that eats other living things to survive. Primary consumers eat producers, secondary consumers eat primary consumers, and so on. There are always many more primary consumers than secondary consumers, etc.