Which of these major events occurred during the Precambrian time?

1. Cyanobacteria filled the water and air with oxygen.
2. Landmasses were all below water
3. Trilobites became extinct.
4. People lived on Earth.

Which of these major events occurred during the Paleozoic era?

1. People lived on Earth
2. All animals lived on Earth
3. Flowers first existed on Earth
4. Pangaea, the huge super continent, formed.

Which organism lived on Earth during the Precambrian time?

1. Fern
2. Dinosaur
3. Octopus
4. cyanobacteria

Which organism lived on Earth during the Paleozoic era?

1. Trilobite
2. Dinosaur
3. Pine Tree
4. octopus

trilobite

Which event occurred during the Mesozoic era?

1. Humans lived on Earth
2. The first plants lived on the land
3. Pangaea, the super continent, began to break apart.
4. Cyanobacteria begin to fill the air and water with oxygen.

1. Pangaea, the super continent, began to break apart.

Which organism first appeared during the Cenozoic era?

1. cyanobacteria
2. trilobite
3. wolf
4. dinosaur

Which event occurred during the Cenozoic era?

1. Humans lived on Earth
2. Volcanoes and earthquakes made the surface of the Earth hot and broken.
3. Pangaea, the supercontinent, began to break apart.
4. Cyanobacteria begin to fill the air and water with oxygen

Which organism lived during the Mesozoic era?

1. cyanobacteria
2. Trilobite
3. Wolf
4. Dinosaur