Answer: 73

Answer: 180 degrees
The angles of a triangle always sum to 180 degrees.

Answer: A billion years
Generally, an eon actually often refers to an indefinite amount of time

Answer: 49

Answer: Earth

Answer: O3
Ozone, also known as trioxygen, is an inorganic molecule. It is a pale blue gas with a pungent smell.

Answer: 23,000

Answer: Meteorite
Millions of materials from space enter Earths atmosphere everyday, but most is burned up before it reaches Earth's surface. The heat caused by friction is what causes Meteorite's to glow in the sky.

Answer: Hydrogen

Answer: Venus