mitochondria ref name hillisetal excavates comprise several groups diplomonads parabasalids heteroloboseans euglenids kinetoplastids ref name hillisetal stramenopiles characterized presence tubular hairs longer two flagella include diatoms brown algae ref name hillisetal diatoms primary producers contribute one fifth photosynthetic carbon fixation making major component phytoplankton ref name hillisetal rhizarians mostly unicellular aquatic protists typically contain long thin pseudopods ref name hillisetal rhizarians comprise three main groups cercozoans foraminiferans radiolarians ref name hillisetal amoebozoans protists body form characterized presence
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