How do you set up a proper experiment

Can someone me with questions 15 to 17 plz.

When a septic tank backs up a goes in to clean it out

The gulf stream is a warm water current that flows away from the equator to northern europe. witch of these does it cause. a. crashes of warm and cool water in the ocean b.colder climates near the equator c.large waves on the cost of europe d.warm climates in northern europe