Why are autoinducers small molecules?

Autoinducers are small molecules or proteins produced by bacteria that regulate gene expression. Autoinducer must bind to receptor to turn on transcription of genes responsible for the production of more autoinducer. The receptor stays in the bacterial cell, but the autoinducer diffuses out.

Autoinducers are small molecules or proteins produced by bacteria that regulate gene expression. ... Autoinducer must bind to receptor to turn on transcription of genes responsible for the production of more autoinducer. The receptor stays in the bacterial cell, but the autoinducer diffuses out.

Explanation:

answer; i believe the correct answer is (sporophyte);