The largest units of geologic time are the

Another name for cyanobacteria, the earliest evidence of ancient life, is

Stromatolites are structures created by

What type of volcano forms a layered, composite cone?

Which of the following volcanoes is in the United States?

The ______________ angle added to the altitude angle equals 90°.

______________ is defined as the angular measurement, in degrees, east or west of the Greenwich, or prime, meridian.

The actual amount of time it takes for Earth to rotate 360° on its axis is called a

Our current calendar is the____________ calendar.

Determine the distance in nautical miles between point A, located at 45°N, 75°W, and point B, located at 30°S, 75°W.