How are stromatolite fossils evidence of earths early life?

“Stromatolites are pervasive in the fossil record and are some of our earliest examples of life on Earth,” he says. “The microbial mats that created them were predominantly made up of cyanobacteria, which used photosynthesis – like plants do – to turn sunlight into energy while producing so much oxygen over time they changed the early Earth’s atmosphere to make it habitable for complex life.

what have scientists found to be the most efficient and effective way to insert new sequences into an individual? a-scientists have created genetically altered foods that release dna during digestion. b-scientists use viruses to insert specific gene sequences. c-scientists irradiate genes so that they can be absorbed through the skin.