Electromagnets are used for various purposes but I fathom in this instance, the questioner is asking about how electromagnetics can be used to attraction or repulsion.
Example, electromagnets are used for attraction in cranes which attach them to containers in order to lift them.
Meanwhile, Maglev trains use electromagnets repulsive properties.
Answer:
4
Explanation:
G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²
= Mass of Earth
= Mass of Moon
r = Distance between Earth and Moon
Old gravitational force

New gravitational force

Dividing the equations

The ratio is 
The new force would be 4 times the old force
Answer: motion parallax
Explanation:
Motion parallax refers to a form of depth perception whereby objects that are closer to an individual appears to move at a faster speed than the objects that are far.
Therefore, Kate is riding on a train and notices that the wildflowers by the side of the tracks seem to be moving by much faster than the mountains in the distance is an example of motion parallax.
Answer:
In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46.