Yes. A body in projectile motion is acted by only one force (gravity in case of heavenly bodies and electric force in case of charges moving between plates). This force is constant and is equal to $mg.$ So, the acceleration of the body is also constant which is equal to acceleration due to gravity $g$ and acts vertically downwards.
Yes. A body in projectile motion is acted by only one force (gravity in case of heavenly bodies and electric force in case of charges moving between plates). This force is constant and is equal to $mg.$ So, the acceleration of the body is also constant which is equal to acceleration due to gravity $g$ and acts vertically downwards.