Stonehenge is thought to be a(n) ________.

Stars with over eight times the mass of the Sun have relatively short life spans and terminate in a brilliant explosion called a ___________.

A self sustaining reaction where some of the products are able to produce more reactions of the same kind is called a ________________.

Which of the following planets has no moons?

A balanced equation is defined as one where _______.

The elements heavier than iron in Earth were formed by _________.

The deflection of moving objects to the right in the Northern Hemisphere and to the left in the Southern Hemisphere is known as the __________.

The fact that there are seasons on Earth is largely due to _______.

Comets in the solar system are believed to originate in either the Oort Cloud or the ______.

The cosmic microwave background radiation is the ___________________.