sentences: endangered cells top in kinds
docs: endangered_species is species. large_cell is abnormal_cell. endangered_species is non_empty_collection. hiv_cell_invasion is viral_invasion_of_cell. endangered_species is endangered. killer_t_cell is t_cell. one_kind_of_cell is prison_cell. death_cell is cell. gram_positive_cell_wall is bacterial_cell_wall. large_cell is cell.