How many letters does the top answer for “a large group of bacteria having rigid cell walls; motile types have flagella” have?

The most common answer is eubacteria (10 letters).

Crossword clue: a large group of bacteria having rigid cell walls; motile types have flagella

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

eubacteria 10 letters wn-def

a large group of bacteria having rigid cell walls; motile types have flagella

eubacterium 11 letters wn-def

a large group of bacteria having rigid cell walls; motile types have flagella