Question

1. which objects in the picture above would make good reference points? why?

Explanation:

A good reference point is an object that is stationary (or assumed to be stationary) and distinct, so it can help determine the position or motion of other objects. In the picture, the trees in the background (or the person, or the dog if we consider relative motion, but stationary objects like trees are better) are relatively fixed. For example, the trees: they appear to be in a fixed position (not moving relative to the scene), so when observing the motion of the person or the dog, the trees can be used to see how far or in what direction these moving objects have changed position. The person or the dog could also be reference points for each other, but stationary objects like the distant trees are more reliable as they don't move (or move very little) in the context of the scene.

Answer:

Objects like the distant trees (or the person, or the dog) can be good reference points. Trees are good because they appear stationary, helping to observe the motion/position of the person or dog. The person or dog can also be reference points for each other as their positions relative to one another can be tracked. (A more precise answer could focus on the most stationary - like the trees in the background, as they are less likely to move, so they provide a stable frame of reference to determine the movement of the person and the dog.)