They make your muscles stronger and keep the bones, heart, and lungs in good condition. It implies that you have less chance of blood clotting and heart attack. one can balance his mood well and is likely to experience less stress in life.It also helps us to practice discipline.
The phrase "light year" is a <u><em>distance</em></u> ... it's the distance that light travels through vacuum in one year.
When you look at an object located 1 light year away from you, you see it as it was 1 year ago.
If a star located 10 light years away from us suddenly brightens, or dims, or explodes, we see the event <em>10 years later.</em>
A pure substance that cannot be decomposed by ordinary chemical change. . Energy can be converted from one form to another, but it cannot be created or destroyed in ordinary chemical or physical means.