Thermal energy transfer. Ex. Hot to Cold
The answer to the first question is a.
Ice actually has a very different structure than liquid water, in that the molecules align themselves in a regular lattice rather than more randomly as in the liquid form. It happens that the lattice arrangement allows water molecules to be more spread out than in a liquid, and, thus, ice is less dense than water.
SI is a base 10 standardized system. I hope this helped and if not I highly recremend talking to your teacher or a parent.
