Answer: D
Explanation:
When an object falls gravity is pulling down on it and is picking up speed, but as it gains speed air resistance becomes a faster. Air resistance increases with speed. And that force keeps it from accelerating eventually the object will pick up speed such that the force due to air resistance will keep it from getting any more speed at that point force due to air resistance is equal to its weight (mg) and the net force is equal to zero so it won’t accelerate any more at that point it is said to be moving in terminal velocity.
When an object has reached terminal velocity, it will have a constant velocity
Im guessing it's (a) since the numbers go in chronological order and you read the periodic table left to right
Answer:

Explanation:
m = Mass of each rod
L = Length of rod = Radius of ring
= Mass of ring
Moment of inertia of a spoke

For 8 spokes

Moment of inertia of ring

Total moment of inertia

The moment of inertia of the wheel through an axis through the center and perpendicular to the plane of the ring is
.
Different layers represent clouds made of gases that condense at different temperatures.