It is either A or C. i hope i could help. if not im really sorry
Answer:

Explanation:
From the question we are told that:
Mass 
Drop distance 
Generally the equation for Spring Constant is mathematically given by



Answer:
Natural science is concerned with the description, prediction, and understanding of natural phenomena based on empirical evidence from observation and experimentation. It can be divided into two main branches: life science (or biological science) and physical science.
Explanation:
Answer:
Here are 5:
Distance from source to receiver
Wind speed and direction
Wind gradients
Temperature gradients
Atmospheric attenuation
and there are many more...
Hope that was helpful.Thank you!!!
Answer:
Stars are at large distances that even light takes thousands of years to reach us from there.
for example, alpha centauri is 4300 light years away from earth and it is considered the nearest star to us, this means that light from there takes 4300 years to reach us and with a spaceships that can move with the speed of light is would take us 4300 years to get there which is imposible to live for that long.
hence, it is difficult to move between the stars.