In a gasoline engine, the area in the cylinder head where the air-and-fuel mixture is burned is called the
a. combustion chamber.
b. intake valve.
c. cylinder.
d. piston.

b..

is the correct one

explanation:

covalent bonds form as valence electrons are shared between two atoms. lewis structures and structural formulas are common ways of showing the covalent bonding in organic molecules. formal charge describes the changes in the number of valence electrons as an atom becomes bonded into a molecule.

a