The correct answer is Protozoans.
Protozoans are best described as uni-celled eukaryotic organisms, both free-residing or parasitic, which feed on organic matter together with different microorganisms or organic tissues and particles. back then, the protozoa have been seemed as "one-celled animals," because they regularly possess animal-like behaviors, together with motility and predation, and lack a mobile wall, as discovered in plant life and plenty of algae.
oxygen flow is low and his lungs do not have a lot of capacity
Two partial cells, which are still forming into real cells
Cells within the body are properly arranged and their production uses up resources of the body. For example, red blood cells use iron while being produced. The body must dispose of cell properly to maintain the orderly arrangement of cells; for example, if dead skin cells were not removed, we would lose feeling in our skin due to the layer of dead cells. Moreover, the body must work to minimize wastage. This is why some of the iron from red blood cells is removed and reused.
