The first land plants appeared around 470 million years ago, during the Ordovician period, when life was diversifying rapidly. They were non-vascular plants, like mosses and liverworts, that didn't have deep roots
A water molecule (H2O) will have a slightly positive side, and a slightly negative side. The oxygen side of water is the one that is negative, while hydrogen side tends to be more positive. When a molecule has a half negative and half positive side like water does, it is called a polar molecule. :D
2) The concentration of O2 will increase inside the cell.
The cell will want to reach equilibrium, meaning that there should be an equal number of oxygen inside and outside the cell. In the picture, more oxygen is shown outside the cell than inside so oxygen will flow into the cell until it has reached equilibrium. Therefore, the concentration of O2 will increase in the cell.
Hope this helps!!