Answer:
I Think its ABC
Explanation:
No air is the lightest
Helium is lighter than regular air that's why it goes up so then the regular air would be heaviest.
Answer:
1.Stronger bones 2.Joint flexibility
Answer:
if the object is not in motion
Explanation:
Answer:
The speed of the resistive force is 42.426 m/s
Explanation:
Given;
mass of skydiver, m = 75 kg
terminal velocity, 
The resistive force on the skydiver is known as drag force.
Drag force is directly proportional to square of terminal velocity.

Where;
k is a constant

When the new drag force is half of the original drag force;

Therefore, the speed of the resistive force is 42.426 m/s
Answer:
I think it is television and radio wave