prep 3 , unit 3

The continuous expansion of the universe is due to as time passes.

• separation of galaxies

• approaching of galaxies

• stability of galaxies

• slow of galaxies motion

Scientists believe that the matter of the universe was a .....ball of high pressure and high temperature.

• liquid

• solid

• gaseous

After minutes from the Big Bang, the temperature becomes........... million degrees.

• 100

• 1000

• 10000

• 100000

.........began to form after 3000 million years of the Big Bang.

• Galaxies

• Stars

• Planets

• Ancestral galaxies

The two gases which produced galaxies, stars and universe over millions of years are

• oxygen and helium.

• oxygen and carbon dioxide.

• hydrogen and helium.

• hydrogen and carbon dioxide.

Within minutes after Big Bang, hydrogen gas was formed by a percentage of

• 25%

• 50%

• 75%

According to the Big Bang theory, within minutes from the origin of the universe, the ratio of hydrogen to helium is

• 75: 1

• 25:1

• 3:1

• 1:3

The Milky Way galaxy took its disc form after about the Big Bang. million years from

• 1000

• 3000

• 5000

• 10000

The earliest life forms began to appear on the Earth after about.......... million years from the Big Bang.

• 15000

• 13000

• 12000

• 10000

Planets rotate around the Sun by the effect of the gravity of

• the Sun.

• Jupiter.

• the Earth.

• the moon.