Hydrophilic means that it likes water so it will easily break down in water
hydrophobic will do the opposite and repel water
There are many reasons to why slaves were essential in the colonial economy:
Slaves were generally used more in the south, because large plantations were found there, which meant that the need for large amounts of workers.
Slaves provided cheap labors, and as they were not "citizens" of the US, they were not allowed their rights.
Slaves were also relatively easy to buy and replace, however, their survival rates were not that good after they traveled long distance.
etc.
hope this helps
I believe its A. I could be incorrect though.
Vaccines and shots are typically made of a small controlled portion of the virus or disease to cause immunity to the large scale types.