What is Earth's second atmosphere?

Why does water fill the bottom of a glass rather than cling to the side

The distance of mars to the sun is 1.5 that of earth. "how many earth years does it take for mars to orbit the sun?"

Which type of heat source is the cleanest? A. open fireplace B. wood stove C. hot water radiant heat

An axe blade is an example of which simple machine

If the forces acting upon an object are balanced, then the object A) All of these B) Might be stopped. C) Might be moving at a constant velocity D) Is not accelerating

Hydroelectric power uses: wind water coal the sun

Two lightweight metal spheres are suspended near each other from insulating threads. One sphere has a net charge; the other sphere has no net charge. The spheres will: A. Attract each other B. Exert no electrostatic force on each other C.

Read the given list of organisms. squirrel, zebra, tortoise, rabbit, horse What best describes the role of these five organisms in a food web?

What are the SI units for specific heat capacity

What are starburst galaxies and what do they have to do with galaxy evolution?