When an object is falling and reaches a constant velocity, the net force on the object is <em>zero</em> (it's not accelerating), and the weight of the object is equal to <em>the force of air resistance against the object</em>. (choice-D)
My answer is in the picture
Swipe the pictures to see the others
The Correct answer: 18
They are also known as families because they are in the same column.