Mutualism Commensalism Parasitism Predation Competition Symbiosis 2. Snakes kill chicken and rats for food. 3. Weeds and garden plants competing for sunlight and nutrients form the soil. 4. Orchids attached to the trees. Orchids use the tree for support. Trees, on the other hand, are not harmed nor they get nutrients from the orchids. 5. Bacteria living in the digestive tract of the cows. Cows eat grass that contains cellulose, however, they don't have enzyme cellulase to break down cellulose to simple sugars, so the bacteria living in their stomach digest the cellulose. The cows, on the other hand, provide them shelter. 6. The zebras outwitting one another for food and water supply.​