Please explain it’s in the photo

Since air resistance actually stops vehicles and goes in a vector opposite to the direction of the vehicle and slows it down. Vehicles would want to make vehicles aerodynamic. Many cars bump into air molecules therefore making air resistance. Aerodynamic cars will lesser the allowance of bumping into said molecules. Thats why cars like to cut down on air resistance

Air resistance is friction.  

-- Friction steals kinetic energy.

-- A car gets kinetic energy by burning gasoline, and uses the kinetic energy to get where it needs to go.  

-- If anything steals the car's kinetic energy, then the car has to burn more gasoline to get where it needs to go.

-- Gasoline costs money.

-- Anything that steals a car's kinetic energy costs you more money to operate the car.

(Another thing that takes kinetic energy away from the car is the car's brakes. The driver uses the brakes when he WANTS to slow down or stop, so it's not stealing, but it still costs kinetic energy and money.)

a.   mass number from atomic number