Examples of symbiosis in nature.

Human and intestinal bacteria are an example of symbiosis. Recall that symbiosis is a beneficial union of certain organisms. The bacteria help us with digestion. They secrete many digestive enzymes that are not able to be secreted in our body. Also, the symbiosis of fungi and unicellular algae forms lichens. They do not need organic matter, since algae synthesize them themselves, and fungi absorb water and accumulate organic matter. Therefore, lichens are incredibly tenacious organisms.