The half-life of carbon-14 is about 6000 years. Assume that a sample of charcoal formed by burning of living wood 15,000 years ago. How much of the original carbon-14 would remain today?

Low ridges of land, parallel to the coast, along the Atlantic and Gulf coasts, are known as ________.

________ has the same mineral composition as andesite.

In general, cinder cones are much larger than shield volcanoes.

________ has the same mineral composition as andesite.

Longshore sand transport and longshore currents depend on waves impinging ________ to a shoreline.

Muscovite, biotite, and chlorite are common minerals found in phyllites and schists.

When a permanent stream enters a desert area, what happens to its discharge?

Continental crust is generally thicker than oceanic crust.

________ occur at about the time of the first quarter and third quarter phases of the Moon.