Final answer:
Water moves from areas of lower osmolarity to higher osmolarity; thus, it will move towards the 3Osm CaCl2 solution, which has a higher osmolarity than the combined 1Osm sucrose and 2Osm O2 solution.
Step-by-step explanation:
The comparison between a 1Osm sucrose and 2Osm O2 solution versus a 3Osm CaCl2 solution involves understanding the concept of osmolarity and the movement of water during osmosis. Water will naturally move towards the solution with higher osmolarity because it has a lower concentration of water molecules.
CaCl2 dissociates into three ions (one Ca2+ and two Cl−), which means a solution of CaCl2 will have a higher osmolarity than the same molarity of a solution with a solute like sucrose, which does not dissociate into ions. The combined osmolarity of the sucrose and oxygen is less than that of the CaCl2, hence water will move towards the CaCl2 solution.