I feel the answer is cell membrane .
The cell membrane is a semipermeable protection and covering for the cell.
Please mark me as brainliest, if this helped.
T-cells are a type of white blood cell that circulate around our bodies, scanning for cellular abnormalities and infections.
Im not 100% sure but the best answer I can give is Prokaryotes because they came to be around the time oxygen did as well.
Wear safety goggles while looking into the opening of the test tube