Answer: Aristotle and Ptolemy had both assumed each planet is attached to a single sphere, but geometers and astronomers could employ a number of such spheres to generate the observed motions of the planets.
Explanation:
I believe the answer you are looking for has to do with cells, they are the basic building block of life and are the smallest life that can support itself.
Answer:
Erythrocyte
Explanation:
Erythrocytes, or otherwise called, red-blood cells are responsible for transporting oxygen and carbon dioxide to and from the cells and tissues. The reason for this is because of a protein called hemoglobin. The hemoglobin found in erythrocytes allow for transportation of oxygen + CO2 to and from cells.