What force keeps us on the ground?

How many planets are in the solar system?

What gas makes up most of the Sun?

What type of rock is formed from cooled lava?

What is the atomic number of hydrogen?

What is the main function of red blood cells?

What is the most common element in the universe?

What type of energy is stored in a battery?

What is the process of converting water into vapor called?

What is the smallest bone in the human body?