Answer:
The earliest oxygen-producing life forms were Cyanobacteria. Besides Cyanobacteria, these tiny organisms have another name known as blue-green algae
Explanation:Some scientists think that 2.4 billion years ago is when organisms called cyanobacteria first evolved, which could perform oxygen-producing (oxygenic) photosynthesis. Other scientist think that cyanobacteria evolved long before 2.4 billion years ago but something prevented oxygen from accumulating in the air
Answer:
Can you provide more details please?
Explanation:
In eukaryotes, the DNA strands are linear, and DNA polymerase can't replicate the very ends of the DNA strands! These ends are "protected" by repeated sequences called "telomeres." Either the chromosome gets shorter with each replication, or else a special enzyme-nucleic acid complex called telomerase adds new telomeres to the ends. A prokaryotic chromosome is circular and thus does not have the problem of having ended.
<span>Eukaryotic DNA is wound around histones, coiled, and supercoiled -- to replicate it, there have to be unwinding mechanisms, and mechanisms to reduce the degree of coiling. In prokaryotes, the winding problem is much less, and there aren't any histones.</span>
