sentence: Protozoan parasites are also ubiquitous.
sentences_before: There are several other invertebrate phyla which are wholly or largely parasitic. Flatworms and roundworms are found in virtually every wild species of vertebrate.
sentences_after: Hence parasitism is almost certainly the most common feeding method on Earth.
concept_name: protozoan parasite
headings: Co-evolution Parasitism Rapid speciation