I'm not sure if this is exactly correct, but to complete photosynthesis, plants need carbon dioxide and water. Usually sunlight as well. If you are supposed to be specific, you could put H2O. I hope I answered your question!
A) A textbook definition would be that genetic drift is: a random change in allele frequency caused by a series of chance occurences that cause an allele to become more or less common in a population. In layman's terms, this means that genetic drift happens when luck makes the genetic pool of the population to deviate from what is expected.
B) The cause for this genetic drift is the aformentioned couple. Because amish communities are small and they select partners from their community, having even a couple of carriers of alleles in a community can make the allele freuency much larger than expected; for example, if the community was 100 persons, the percentage would be in the order of 1%, still much larger than the general population. Thus, the cause here is that a small population had a couple of carriers.
C) Sexual reproduction leads to a mixing of alleles from both mother and father and helps diversity. When a population is isolated, the gene pool is fixed and no new genes can come in, reducing diversity. Also some people that have an allele might die, hitting diversity even more. Finally, having a small population creates a strong pressure in some circumstances that leads to elimination of some traits and diversity.
Science can only explain logical questions and provide answers to things that only can be scientifically proven. Things that are asked in society like religion can not be further explained. The reason why we have religion is because we have always believed in something in history. Either is was made up or concocted out of no where, humans have always believed in something. But what science can't explain is the miracles and things that have happened. Like Jesus, they can't prove that he performed miracles or was the Son of God. They can't prove he and his body ascended into heaven. Science can't explain that God is real. Yet the only thing you can do is believe in it, and trust the Bible accounts are accurately true.
