Nylon is very resistent to organic solvents, but when you boil it in acidified water is will decompose. Nylon is made by a condensing reaction, that is a water molecule is split off to join two monomers together to form an amide bond. With the help of a water molecule that reaction can be reversed to split in into the monomers again.

ABS is resistent to many but not all organic solvents (think acetone smoothing here), but totally resistent to water.

PLA has the label of being biodegradable, however that is not fast. Many substances that are touted as 'biodgradable' take a very long time to do so. If a lab test shows that it is in principle possible (even after a very, very long time, and only under specific conditions), it will be labeled biodegradable to boost sales.