Earth's mantle is

a. a layer of molten metal.

b. a layer of hot rock.

c. a dense ball of solid metal.

d. a layer of rock that forms Earth's outer skin.

Briefly describe what has happened (or is happening) to each of the following modes of public transportation in U. S. cities? -trolleys -buses -rapid transit (subway & fixed rail line)

How many oceans are embracing Europe?

Fertilizers contain fixed nitrogen. how could the widespread misuse of this fertilizer lead to an imbalance in the oxygen cycle

What a refugee is and state the type of refugees that we have around the world?

If you observe an impaired driver a safe behavior for you would be

How the moon was formed

Which of the following kinds of environmental problems is irreversible? A. Water pollution B. Extremely high atmospheric carbon dioxide levels C. Polar ice pack melting D. Species extinction

How can we calculate the mean temperature of a particular place?

What conditions make for a violent volcanic reuption?

Why is the Amazon River called the Ocean River?