The sun reaches the zenith (directly overhead) at midday ___________.

The first humans arose ________ the last dinosaurs.

We never see a crescent jupiter from earth because jupiter __________.

Galileo challenged the idea that objects in the heavens were perfect by ________.

The velocities of seismic waves traveling from earthquake foci ________.

The light collecting area of a telescope is larger in telescopes which have a larger ____________.

Planets revolve around the sun along _____ paths because of gravity.

Planetary orbits that are more elliptical have a greater _________

People once believed that all planets and stars orbited around ____.

We can estimate the age of an open cluster of stars by examining _________.

The energy that is released in the hydrogen fusion reaction comes from __________.