Sample Response: Personal water filters solve the
problem of having access to drinking water anywhere.
They are available and affordable. The materials used to
make them are durable. They remove bacteria but there
are still risks, because they cannot filter heavy metals or
viruses. Still, the benefits outweigh the risks.

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

Wavelength,frequency,and energy are related.what happens to a wave as it’s wavelength gets shorter?

How does the entropy of steam compare to the entropy of ice?