The specimen of choice for diagnosing "Trichomonas tenax" trophozoite is mouth scrapings. Their life cycle alternates between a swimming trophozoite and an infective, resistant cyst. In the life cycle is an extracellular feeding stage known as the trophozoite. The cyst stage of the parasite is usually smaller than the trophozoite, round, and quadrinucleated. The transformation of flagellate to trophozoite occurs within a few hours. However, as parasites transition to the trophozoite stage Maurer's clefts become fixed in place. "Acanthamoeba" has two evolutive forms, the metabolically active trophozoite and a dormant, stress-resistant cyst. These medications disrupt the cell wall of the trophozoite organism, leading to its death. The life cycle of "Giardia" consists of a cyst form and a trophozoite form. Within the red blood cell, the protozoa become cyclical and develop into a trophozoite ring. Once inside the nasal cavity, the flagellated form transforms into a trophozoite. Some arsenical compounds are shown to treat the trophozoite stage, like carbarsone. In the erythrocyte the merozoite form a ring-like structure, becoming a trophozoite. The trophozoite parasitises erythrocytes or other tissues in the vertebrate host. " coli" has two developmental stages, a trophozoite stage and a cyst stage.