Whereas gram-negative bacteria such as the Proteobacteria often use ________ as autoinducers, quorum-sensing gram-positives more commonly use ________ that act as autoinducers.
a) Acyl-homoserine lactones; peptides
b) Peptides; acyl-homoserine lactones
c) Ribosomal RNA; lipids
d) Lipids; ribosomal RNA