I went to the museum of natral history.

The Universe was formed about 15 billion years ago.

The earth was formed about 4.6 billion years ago during the Big Bang.

Long ago, there was only one continent called Pangea.

As time goes by, it has been divided into 6 continents.

There are 8 planets in the solar system.

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Pluto is not included in the solar system because its revolving pattern is diffrent from other planets.

When the planet turns on its axis, it is called a rotation.

This takes 24 hours. It is connected to day and night.

When the Earth revolves around the Sun, it is called a revolution.

This takes one year.  It is connected  to the winter solstice and the summer solstice.

Horoscope is a place where stars are.

Volcano is an opening in the earth's crust which magma is ejected.

Baekdu mountain and Halla mountain are made by volcanoes.

They are inactive volcanoes.

Cyanobacteria are living cells that produce oxygen through photosynthesis.

Carnivorous dinosaurs eat meat. Herbivorous dinosaurs eat plants.

I saw lots of bones of dinosaurs. 

I couldn't believe that they had existed on the earth.