Choanoflagellates are single-celled eukaryotes that feed on bacteria. In the presence of their food bacteria, some choanoflagellates develop multicellular structures in which the individual choanoflagellate cells are attached to one another. Based on this observation, it may be assumed that:

a) choanoflagellates are complex multicellular organisms, because they alternate between single-celled and multicellular states.
b) the choanoflagellate cells use cadherins to attach to each other.
c) the choanoflagellates use integrins to attach to each other.
d) in the presence of food bacteria, each choanflagellate gets more food when feeding in a cluster than they would when feeding individually.

In reference to the main characteristics of Choanoflagellates, it is true that this single cell organisms use cadherins to attach to each other (option b).

Explanation:

Choanoflagellates are eukaryotic, unicellular and heterotrophic organisms, whose main source of food is bacteria. Phylogenetically they have been related to higher animals, so many consider them to belong to the Animalia kingdom.

An important characteristic of choanoflagellates is their way of forming colonies that confer the appearance of multicellular organisms. These intercellular junctions are achieved by transmembrane proteins - which act as adhesion molecules - called cadherins.

Cadherins are found in the structure in the form of a collar that serves to trap bacteria. Regarding the feeding behavior of choanoflagellates, It is useful to add that bacteria can bind to a specific receptor found in the coanoflagellated surface collar.

It has not been proven that choanoflagellates have integrins in their structure.

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Choanoflagellates link