Question

The earliest fossil records of bacteria-like organisms, dated at over 3 billion years, ________.

1) are too spotty to allow us to trace lines of descent to present-day organisms


2) unquestionably belong to cyanobacteria

3) show that early cells had membranes made of short amino acid chains

4) used only RNA molecules for both information storage and chemical catalysis

5) already contained endosymbiotic organelles

Answer 1

The earliest fossil records of bacteria-like organisms, dated at over 3 billion years, unquestionably belong to cyanobacteria.

Step-by-step explanation:

The earliest fossil records of bacteria-like organisms, dated at over 3 billion years, unquestionably belong to cyanobacteria. Cyanobacteria are photosynthesizers and were likely responsible for the production of oxygen on ancient Earth. Stromatolites, solid rock formations, provide strong fossil evidence of oxygen-producing photosynthetic bacteria that date back almost 3.5 billion years.