An object is dropped and is in free fall. each second, the position of the object is marked. the distance between each mark is measured. which of the following is correct? a. as the object falls, the distance between marks decreases because the object's speed is constant. b. as the object falls, the distance between marks decreases because the object's speed is increasing. c. as the object falls, the distance between marks increases because the object's speed is increasing. d. as the object falls, the distance between marks increases because the object's speed is constant.