Biological interrelationship means that there are direct or indirect relationships among all of the living organisms in this universe. The common example of biological interrelationship is Food chain. Every organism is the food of other organism like a goat eats plants and a lion eat goats. These interrelationships form a food web. The association between algae and fungi or lichens also shows a mutual relationship between the two different organisms. Therefore, the term biological interrelationship shows the beneficial or harmful relationships among the organisms.