Predation Competition Mutualism Commensalism Parasitism Scavenging Competition Herbivory Amensalism Coevolution 25. 21. Goat eating grass 22. Orchids growing on the branches of a tree 23. A heron eating the ticks from the back of a car 24. Butterfly sipping nectar of a flower Eagle preying on a snake 26. Ornamental grasses and day lilies 27. Barnacles on a turtle's shell Aphids and ants on a branch of a tree 29. Lice on human hair 30. Tapeworms in human 28.