• categorize
• didactics
• pedagogy
• phylum
• taxonomic category
• directed study
• elective course
• substitution class
• sizing
• chytridiomycetes

class arachnida  class act  class anthozoa  class anthoceropsida  class acrasiomycetes  class actinozoa  class amphibia  class action  class angiospermae  class aphasmidia