What is the second law of thermodynamics

Explain earth's motion, using the terms "precession" and "rotation" in your answer.

Which features on mars point to the possibility of liquid water on the planet? impact craters with sharp rims volcanic cones with craters gullies and stream-like channels mountain ranges with faults

Which of the following is the main energy source for the sun? a. fission of hydrogen b. fusion of hydrogen c. fusion of helium d. fission of iron