3 What is compression?
A
When alr molecules move apart from one another.
B
When alr molecules collide with one another.
C
When alr molecules become packed tightly together.
D
When alr molecules move around freely.

The answer is C, “when air molecules become tightly packed together”

The answer is falsegravitational force is independent of medium and depends only on the masses of the two objects and the distance between them.

Electron equations of the given changes are as follow,a)                              cu      →      cu⁺²  + 2e⁻b)                              mg⁺²  +  2 e⁻      →      mgc)                              cl⁻    →      cl  +  1e⁻d)                              s  +  2 e⁻    →      s²⁻e)                                o²⁻      →      o  +  2 e⁻f)                              p  +  3 e⁻    →      p³⁻g)                              fe²⁺    →      fe³⁺  + 1 e⁻h)                              s²⁻    →      s⁴⁺  +  6 e⁻