Which choice describes bacteria that grow in filamentous structures?

Filamentous bacteria are characterized by their growth in long chains or filaments, which distinguishes them from other bacterial morphologies. These structures can be comprised of many cells that remain attached after cell division, giving rise to a characteristic filamentous appearance. This form of growth is seen in various bacterial groups, including some actinomycetes and certain cyanobacteria, which can form extensive networks of filaments.

In contrast, cocci are spherical bacteria that do not typically form filaments; they may exist as single cells, pairs, chains, or clusters, but always retain a round shape. Bacilli are rod-shaped and can appear as single cells or in pairs but do not characterize as filamentous structures. Spirilla are spiral-shaped bacteria, which may twist and turn but do not grow in filamentous arrangements either. Therefore, the correct choice accurately captures the defining trait of filamentous bacterial growth.