<The Museum of Natural History>

 Today, I went to the Museum of natural history. In there, I learned about the universe and the earth. The universe was borned 15billion years ago by Big Bang. About 4.6billions years ago, sun and planets appeared. They became solar system. There are 8 planets in solar system.They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The third planet, Earth, has Cyanobacterias and they produce oxygen.This process is called Photosynthesis.

 The earth has four eras. They are Precambrain, Paleozoic, Mesozoic, and Cenozoic. In  Precambrian, Cyanobacterias produce the oxygen and in Paleozoic, the creatures began to live on the ground. In Mesozoic, the dinosaurs appeared. The dinosaurs are separated by Carnivore dinosaurs and Herbivorous dinosaurs. Carnivore dinosaurs eat meat, so they have strong teeth and claws. Herbivorous dinosaurs eat plants and they should protect themselves, so they have small teeth and hard horns. They were extincted by meteorite. In Cenozoic, there were mammoths and humans. Mammoths are simmilar to elephants, but they are more stronger than elephants. They were extincted, too. At first time, humans look like monkeys, but today, humans become different from monkeys.

 I learned about the universe and the earth so much. I hoped to go there again. They are very interesting.