Answer:
NASA's Chandra X-ray Observatory and other telescopes such as the Hubble telescope.
Explanation:
Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies.
The above observations have provided the strongest evidence yet that most of the matter in the universe is dark.
Answer: a) 8.2 * 10^-8 N or 82 nN and b) is repulsive
Explanation: To solve this problem we have to use the Coulomb force for two point charged, it is given by:

Replacing the dat we obtain F=82 nN.
The force is repulsive because the points charged have the same sign.
1 ft²= 0.09290304m²
so:
43560ft²= 0.09290304m²×43560
= 4,046.8564224 m²