99 percent of the earth's atmosphere by mass is made up of only elements. These elements are

A) Carbon and oxygen

B) Nitrogen and oxygen

C) Hydrogen and oxygen

D) Helium and hydrogen

Which of the following is not a step in the inquiry process A. Classify B. Summarize C. Investigate D. Observe (APEX)

Which stage of Kohlberg's theory of moral reasoning is based on one's personal code of ethics? A. unconventional B. conventional C. preconventional D. postconventional

The typical unit for a period used with Kepler's third law is

A motor spins up the flywheel with a constant torque of 50 n⋅m. how long does it take the flywheel to reach top speed?

We have two equal size boxes, A and B. Each box contains gas that behaves as an ideal gas. We insert a thermometer into each box and find that the gas in box S is at a temperature of 50°C while that in B is at 10°C.

An elevator has mass 600 kg, not including passengers. the elevator is designed to ascend, at constant speed, a vertical distance of 20.0 m (five floors) in 16.0 s, and it is driven by a motor that can provide up to 40 hp to the elevator.

When two objects collide and stick together, what will happen to their speed, assuming momentum is conserved? They will move at the same velocity as whichever object was fastest initially.

Which planet shows evidence of water erosion?

What do nuclear fission and nuclear fusion have in common?

When plug prongs are connected to the metal case of an appliance, a part that should always be placed next to the case is a a. flat metal washer. b. hexagonal aluminum shoulder. c. steel nut. d. mica washer.