The layer of electrically charged molecules and atoms which spans 40-250 miles above ground called ionosphere causes the display of the aurora and the reflection of radio waves back to earth.
a) 
The acceleration due to gravity at a certain location on Earth is given by

where
G is the gravitational constant
M is the Earth's mass
R is the Earth's radius
h is the altitude above the Earth's surface
At the top of Mt. Everest,
R = 6380 km = 


With
(1)
At the Earth's surface,
R = 6380 km = 
h = 0
g = ?
So
(2)
By doing the ratio (2)/(1), we find an expression for g in terms of g':

And therefore,

b) 519.3 N
The weight of an object near the Earth's surface is given by

where
m is the mass of the object
g is the acceleration of gravity at the object's location
In this problem,
m = 50 kg is the mass of the object
g' = 9.77 m/s^2 is the acceleration of gravity on top of Mt Everest
Susbtituting,

Explanation :
The points regarding the gravitational waves are as follows :
(1) Gravitational waves are predicted to travel through space at the speed of light. So, the speed of gravitational waves is also equals
.
(2) The first direct detection of gravitational waves came in 2015. It is detected using a advanced LIGO detectors.
(3) The existence of gravitational waves is predicted by Einstein's general theory of relativity.
Hence, the correct options are (B), (D) and (E).
Answer: C. can robots be trained to follow a moral code?
Explanation: