The main difference between Gram$-$negative bacteria and Gram$-$positive bacteria is:

peptidoglycan

all of the above

the amount of N $-$acetylglucosamine $($NAG$)$

the chemistry of the cell wall

the amount of N $-$acetylmuramic acid $($NAM$)$

How many electrons are involved in a covalent bond:

$3$

$2$

none of the above

$1$

all of the above

The statement "Prege$$nglionic axon terminals release acetylcholine." is

Select one:

A$.$ true only for the sympathetic nervous system.

B$.$ true only for the parasympathetic nervous system.

C$.$ true for both the parasympathetic and sympathetic nervous systems.

D$.$ true only for the somatic nervous system.

E$.$ not true for either the parasympathetic or sympathetic nervous systems.