Better health is central to human happiness and well-being. It also makes an important contribution to economic progress, as healthy populations live longer, are more productive, and save more. Many factors influence health status and a country's ability to provide quality health services for its people.
The absolute simplest way to explain E=MC^2 is: a lot of energy from a little mass.
A eclipse of the sun can only occur at a new moon when the moon passes between earth and sun. If the moons shadow happens to fall upon earths surface at a time, you'll see some portion of the suns disk covered or aka eclipsed by the moon.. I hope that helps