Select the most appropriate option that can substitute the highlighted segment in the given sentence. If there is no need to substitute it, select ‘No improvement required’.
Newton, after seeing the apple falling from a tree, began to wonder whether if it moved
towards the earth and not upwards towards the sky.

Correct option is D

The correct substitution for the highlighted segment "whether if it moved towards the earth and not upwards towards the sky" is "began to wonder why."
· The phrase "whether if" is redundant and grammatically incorrect. The correct choice, "began to wonder why," simplifies the sentence and directly addresses Newton's curiosity about the reason behind the apple's movement towards the earth rather than upwards.