How does a modular approach to web design help me as a developer?
A modular approach saves time by adhering to an important tenet of computing: don't repeat yourself or DRY. By making, let's say, your navigation bar a module, you can import it with just one line to every page that needs it. Compare that with writing the same 100 lines of code every time you need a navbar and updating every single page each time you make a change.
Why does ice float on water?
There are hydrogen bonds between water molecules. When the temperature is just above the freezing point, water molecules have enough kinetic energy to overcome the hydrogen bonds and slide freely across each other and assume all sorts of arrangements that make it quite packed. But when water freezes, the molecules do not have sufficient energy and are packed in a regular lattice arrangement that is less dense than water at a slightly higher temperature. Assuming the mixture of ice and water has a similar temperature throughout, ice floats on water.
Are there quotas for international students at top colleges?
Not a specific quota, but if you look at the percentages of international students at top 20 schools and LACs, you'll find that they don't generally exceed 15% of the class. Schools also try to get at least a few students from as many countries as possible so naturally international students from some countries face stiffer competition then those from others.