Answer:
answer is DE I hope it will help you please follow me
Given :
An electron moving in the positive x direction experiences a magnetic force in the positive z direction.
To Find :
The direction of the magnetic field.
Solution :
We know, force is given by :

Here, q = -e.

Now, for above condition to satisfy :

So, 
Therefore, direction of magnetic field is negative y direction.
Hence, this is the required solution.
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.