Which of the following is the best explanation for what causes the shape of a projectile's trajectory? A.
A projectile accelerates in the vertical direction, while velocity is constant in the horizontal direction.
B.
A projectile accelerates in the horizontal direction, while velocity is constant in the vertical direction.
C.
A projectile accelerates in both the horizontal and vertical directions.
D.
A projectile's velocity is constant in both the horizontal and vertical directions.