Question

Please answer it's my urgent need

Answer 1

Answer:

Hold a pencil vertically in the front of you at certain distance against a point on a background like a wall, now veiw the pencil through your left eye closing your right eye and then view the pencil through your right eye closing your left eye.You will notice that with the respect to the fixed point on the wall position of the pencil is changing.This phenomenon is called parallax.The distance between two points of observation is called basis.

Explanation:

Parallax is defined as the apparent shift of a body with respect to another, with the shift of eye.

The distance between planets and stars cannot be measured directly with a metre scale hence indirect method called parallax method