Answer:
Due to presence at early days of the planet.
Explanation:
We only find the remains of single celled organisms in the oldest fossils because the single celled organisms are the organisms that were present in the early days of this planet. These single celled microbes were present about 3.7 billion years ago while on the other hand, the oldest rocks are only a little older i. e. 3.8 billion years so these single celled organisms are considered as oldest fossils on this planet.
Answer: Pulmonary aortic valve
Explanation:
I think that I might be HYENA.
Since they don’t really kill they are mostly “scavengers”
I am not 100% sure though. I hoped I helped at least a little.
