For a basic 500 square feet project in zip code 47474, the benchmark cost to Insulate Your Home ranges between $0.63 - $1.43 per square foot* . To estimate costs for your project: 1.
So in answer to your question, the oldest fossils are stromatolites, and the life forms that created those fossils were prokaryotic bacteria and algae like cyanobacteria.
Like horseshoe crabs, because of their age, stromatolites are considered living fossils.. The oldest known fossil of stromatolites is almost five times older than the oldest fossil of a multicellular organism, which dates back to about 600 million years ago.