They often respond to Quorum sensing which is determined by the cell density. Bacteria cells secrete molecules that can be detected by other bacteria, Quorum sensing allows bacteria to sense the concentration of these signalling molecules to monitor the local density of cells. It used by bacteria to coordinate certain behaviors , such as the production of biofilms.
Nervous system is divided into parasympathetic and sympathetic
They are liquid lipids..
(d)
It is Acceleration.
Explanation: You can probably find it in the back of your book in the definition.