Nebulae are primarily composed of what element?

• Hydrogen
• Helium
• Other hard elements
• Zinc

Nebula's are mixtures of gases and what?

• clouds
• stars
• tiny particles
• dust

The ______is between the orbits of Mars & Jupiter.

• solar system
• asteroid belt
• terrestrial planets
• photosphere

A force of attraction between any two objects is called _____________.

• static electricity 
• rotation
• gravity
• orbit

What do the first four outer planets have in common? 

• They are much larger than Earth and are made mainly of Hydrogen and Helium 
• The are about the same size as Earth and are mostly made of Hydrogen and Helium
• They are must larger than Earth and are mainly made of iron
• They are the same size as Earth and are mainly made of iron

A giant sphere of glowing gases is a ___________

• Galaxy
• Light-year
• Star
• Magnitude

Mercury, Venus, Earth and Jupiter are the inner planets

• True
• False

The __________ has planets, moons, comets, and asteroids.

• solar system
• earth
• rotation
• United States

Earth and the other planets closest to the Sun are made mostly of _______

• gas
• metal
• water
• rock

What is the smallest terrestrial planet?

• Mars
• Venus
• Mercury 
• Earth