| From 1 billion years ago the atmosphere became richer in oxygen until it reached the high level we find in the air today. This might have been the reason why, around 700 million years ago, amazing things began to happen to protozoa. | ||
Useful Links |
| From 1 billion years ago the atmosphere became richer in oxygen until it reached the high level we find in the air today. This might have been the reason why, around 700 million years ago, amazing things began to happen to protozoa. | ||
Useful Links |