was initially water vapor and nitrogen. b. was initially composed of gases pulled from the surrounding solar nebulae, but soon changed to being composed of volcanic gases. c. has always contained abundant oxygen. d. at the time of the Earth's beginning could have sustained life as we know it.

Hurryyy ! a student is asked to describe the path of a paper airplane that is thrown in the classroom. which statement best describes the path of the paper airplane? a. the paper airplane will move in a straight line, according to newton’s first law of motion. b. the paper airplane will drop straight to the ground once its inertia gives in to the force of gravity. c. the paper airplane will create a curved path toward the floor as it is pulled toward earth’s center. d. the paper airplane will orbit around the desk because it is the object with the largest mass in the room.

Which of the following energy sources is not an example of renewable energy? a. a wind turbine farm b. a clean-burning, coal-fired electric plant c. a hydroelectric dam d. a solar panel mounted on a home

Why does sweden and norway have steep roofs