<span>Bacteria are able to sense and respond to a variety of external stimuli, with responses that vary from stimuli to stimuli and from species to species. The best-understood is chemotaxis in the model organism Escherichia coli, where the dynamics and the structure of the underlying pathway are well characterised. So YES they are able too hope this helps </span>
When humans taste or smell, receptors unique to each nerve cell detect the chemical and send signals to the brain, where many cells process the message to understand what we are smelling or tasting. But a bacterium is just a single cell, and it must use many different receptors to sense and interpret everything around it.
Humoral immunity protects the body against extracellular pathogens and their toxins. Cell-mediated immunity protects the body against intracellular pathogens. Recognises pathogens in circulating in blood or lymph.
celluler immunity is very specific compared with humoral
