1. Answer:
It implies that prokaryotes existed before eukaryotes.
It implies that eukaryotes evolved from prokaryotes.
Prokaryote and eukaryote are used as a result of an evolutionary worldview.
All of the three sentences is true. The word "pro-" from prokaryotes means "before". So, prokaryotes sound like an organism that exists before eukaryotes. If you link it with evolution, you can assume that eukaryotes were prokaryotes that evolved.
2. Answer:
food spoilage
flavor food
make cheese
make yogurt
decomposition
Measles can be excluded easily because it was caused by virus, not bacteria. Food spoilage is caused by bacteria. That is why food preservation method would result in killing/inhibiting bacteria. Decomposition is similar to spoilage. Bacteria also used for fermentation in cheese, yogurt or beer.