They can be a barge or a narrow boat.
The large ones are called barges. The smaller ones are referred to as a "John boat" or a duck skiff. In Venice, the transportation boats are called gondolas.
Yes, the Great Barrier Reef can be seen. It's made up of coral atolls and islands, as well as reefs underwater. These reefs underwater can be seen if you go snorkeling, or go on a tour in a glass bottomed boat.
Neptune is a gas planet, thus it has no solid surface (that we've seen yet), thus no canals.
Generically, all sleds are flat and used to coast down hills, but there are many different designs. The Toboggan is a larger sled without runners developed by Native Americans. It is much larger than the Luge seen in Olympic sports. The bobsled is a also seen in the Olympics and is also quite large, sometimes designed for four people.
Gunboats.
Giovanni Schiaparelli claimed to have seen 'canali' on Mars, meaning channels but it was mistranslated to canals.Percival Lowell then made many observations and drawings of what he perceived to be canals and published themThese claims turned out to be false.
Ahmoses
David Barrera (he might have been seen on movies and shows) look him up
Nothing
Noah of Noah and the Ark fame built the first boat. fake
Yes. There have indeed been shark spottings in the canals of Venice. In 1956 an image of what was determined to be a large bull shark in the canals was verified by marine biologists at the Univestity of Bologna. Another sighting was documented and made headlines in the the summer of 1987.
Spotting a red and a green light on a boat at night is an indication that the boat has its bow pointed in your direction. If the boat is under way, it's coming at you.The red light is on the port or left side, the green on the starboard or right. These lights cannot be seen from dead astern, and only one color can be seen from beside (abeam) of the vessel.