What are fun games to play when you are bored?

What comprises a list of main points and sub-points of a topic to include in a presentation? a(n) is a list of main points and sub-points of a topic to include in a presentation.

Match these items. match the items in the left column to the items in the right column. 1. amulet the horizontal beam or crosspiece over a door or window that carries the weight of the structure above it 2. bitumen a large single block or piece of stone 3. lintels sedimentary rock consisting of tiny spherical concentric grains 4. megalithic description of a structure made of large, roughly hewn stones 5. monoliths pictures carved in such a way that the figures stand out from the background 6. nomadic a hydrated (containing water) iron oxide compound 7. ochre a three-part construction of two monoliths topped by a lintel 8. oolitic limestone each part of the body is shown so that the image most easily represents the original 9. relief sculptures a small object worn to ward off evil, harm, or illness or to bring good fortune; protecting charm 10. shaman a trait of people who do not live in one place but rather travel around, hunting and gathering food where they can find it 11. trilithons a tarlike substance 12. twisted perspective a person who acts as intermediary between the natural and supernatural worlds, using magic to cure illness, foretell the future, control spiritual forces, and so on

Why do the terrestrial planet lack hydrogen and helium in their atmospheres?