The direct source of energy to move the sailboat is probably wind, since wind is what pushes the sail of the sailboat, which is what propels the sailboat forward.
Hope this helps!
1983-1984 was when it was discovered
Manure is better than fertiliser. Manure is derived naturally and adds a lot more than just nutrients to the soil. They increase the activity of the microbes in the soil and increase its fertility. On the other hand, fertilisers harm these microbes and cause health issues in the consumers since they are synthesised chemically.
