Well, the density of the water is

so i believe that is what the question is asking for :)
Answer:
the weight of alien is 200 newtons
Explanation:
The computation of the alien weight is shown below:
Given that
Acceleration = 20m/sec^2
And, the mass is 10 kg
So, the weight of alien is
= 20 × 10
= 200 newtons
hence, the weight of alien is 200 newtons
Time = (distance) / (speed)
Time = (4.12x10^16 m) / (3 x10^8 m/s)
Time = 1.37 x 10^8 seconds
Divide the seconds by 86,400 to get days. Then divide the days by 365 to get years.
Time = about 4.35 years
Wave D has the same wavelength as wave A, but the amplitude is lower. The answer is Wave D.