A person standing where the Moon’s penumbra touches Earth will see

What type of fossil is formed when mud fills in the hollow spaces around something hard, such as shell, and then hardens?

A mixture of unconsolidated, weathered earth materials and humus is 

A structural unit that is repeated in three dimensions is called a 

The brightest object in the sky after the Sun and Moon is most often 

Mountains that rise sharply from surrounding land along a steeply inclined fault plane are 

The S-wave is a 

Our Sun is just one of many millions of stars in a group of stars called a 

The layer that is broken up into plates that move in the upper mantle is called the 

The primary difference between fog and a cloud is