During the Proterozoic era, oxygen produced by photosynthesizing bacteria collects in the oceans and then in the atmosphere. Iron present in exposed rocks reacts with this oxygen, and rust colors the ...

Precambrian time covers the vast bulk of the Earth's history, starting with the planet's creation about 4.5 billion years ago and ending with the emergence of complex, multicelled life-forms almost ...

The fossil was discovered in the U.K. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. A bizarre, tentacled creature that lived in the deep ocean ...