The density increases.
When gases are compressed, their volume decreases, and the resulting pressure increases. The temperature will change if either P or V are held constant. Since the volume decreases, then density, or m/V, increases.
P×V ~ T
Answer:
C. Atoms
Explanation:
The basic unit of matter and the smallest, indivisible unit of a chemical element. It comprises a nucleus (neutrons + protons) that is surrounded by a cloud of electrons.
Answer:

Explanation:
From the question we are told that:
Mass 
Drop distance 
Generally the equation for Spring Constant is mathematically given by



The text does not specify whether the resistance R of the wire must be kept the same or not: here I assume R must be kept the same.
The relationship between the resistance and the resistivity of a wire is

where

is the resistivity
A is the cross-sectional area
R is the resistance
L is the wire length
the cross-sectional area is given by

where r is the radius of the wire. Substituting in the previous equation ,we find

For the new wire, the length L is kept the same (L'=L) while the radius is doubled (r'=2r), so the new resistivity is

Therefore, the new resistivity must be 4 times the original one.