Areas with the least dense human populations are in ________

What process(es) play key roles in soil formation?

A. Physical weathering B. Both chemical and physical weathering C. Chemical weathering

Most of Earth's water was derived from ________

A) leftover gases from the nebula B) the Sun's solar wind C) outgassing D) comet vaporization

The ______________ river runs through London.

Fill in the blank(s) with the appropriate word(s).

Brittle stars employ a unique evasive technique that involves detaching an arm if grabbed by a predator

a. True b. False