i) Looking at a typical phase diagram for H2O, with temperature plotted on the horizontal axis, increasing to the right, and pressure plotted on the vertical axis, increasing as you rise, you should see that if temperature is decreased, you are moving to the left into the region labelled "Ice". So the water and the water vapour both freeze.
ii) Looking again at the phase diagram for H2O, you can see that from the triple point (defined as the only condition under which water vapour, liquid water, and ice can coexist in equilibrium), if you increase the pressure, you are moving straight up on the phase diagram into a region labelled "Liquid water". So the ice melts and the water vapour condenses.
The left side of the diagram on page 1 of the pdf found at document http://www.columbia.edu/itc/chemistry/environmental/lectures/week2.pdf shows this phase diagram. The units for pressure are different but there is only one triple point for those three phases of water, so you may disregard the specific values for the purposes of answering your question.
