Areas with the least dense human populations are in ________

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

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