Increasing Order..
So, it's from the little one into the biggest one..
My Answer is
C: Mercury < Earth < Saturn < Jupiter
What Shape of The Earth ?
Is it Round or Flat ?
Subjective Answer..
It depends on what that "certain amount" is.
Answer:

Explanation:
We are given that
The wavelength of sound wave=
1 cm/s=
Speed of sound wave,v=
We have to find the period of the wave.
We know that
Frequency=
Using the formula
Frequency =
Hz
Time period=
Using identity:
Hence, the time period of the wave=
I think it's a solar power might seem strange or futuristic but it's already quite common place you might have a solar powered quartz watch on your wrist or solar powered pocket calculator