Before hominins intentionally chipped stone to make tools, they likely used sharp rocks already shaped by natural forces.

NASA's Perseverance rover has encountered another rock on Mars that has left scientists puzzled.

and fossils of more complex organisms in the newest rocks. This supports Darwin's theory of evolution, which states that simple life forms gradually evolved into more complex ones. Evidence for ...

Rare Metal The metal iridium, which is similar to platinum, is very rare on Earth's surface but is more common in asteroids and in molten rock deep within ... Ranging in size from large chunks ...

and fossils of more complex organisms in the newest rocks. This supports Darwin's theory of evolution, which states that simple life forms gradually evolved into more complex ones. Evidence for ...