20) Mark is looking out the window on the commuter

train and believes that one tree is farther away

than another since it seems to be moving more

slowly. Mark is making his judgment based on

A. motion parallax.

B binocular cues.

C motion relativity.

D the Young-Helmholtz theory.

Answer: A. motion parallax

Explanation:

In the phenomenon of motion parallax, objects that are moving at certain speeds across a particular field of vision, would also appear to move at greater speeds if they're closer to the observer. This remains true even if the object instead of the person is moving

. The phenomenon always arises whether or not the object is moving or that the observer is moving in a manner that is relative to the object's motion. This is because of the distance the object moves in comparison to the proportion of the observers' field of view that it traverses. Thus, motion parallax generally describes one's perception of the position of an object with a three-dimensional space, based on sensing said objects at different positions.