Answer:
Iron
Explanation: It is by mass the most common element on Earth, right in front of oxygen, forming much of Earth's outer and inner core.
Answer:
Kinetic energy
Explanation:
Total energy of any system is always conserved.

E= Total energy
K = kinetic energy
U = Potential energy
Kinetic energy is the energy acquired by the system due to the virtue of it's motion.
Potential energy is the energy acquired by the system due to the virtue of it's configuration.
Also, Kinetic energy 


Answer:
C
Explanation:
Given that a liquid at rest in a fixed container exerts a force perpendicular to the wall of the container. Two students make claims about the microscopic cause of this force. Student A says that the force exerted by individual molecules as they bounce off the wall is always perpendicular to the wall. Student B says that the molecules may strike the wall at angles that are not perpendicular. Which student is correct and why?
The correct answer is option C
Student B . The molecules in a liquid are in random motion at the microscopic scale. For every atom that hits at an angle to one side of perpendicular, there is likely to be another atom hitting at the same speed at the same angle on the other side of perpendicular. On average the nonperpendicular components cancel
It is younger because there had to be rock layers already present for that to be possible.