Grafting is a process of making a piece of a plant grow by attaching it to another plant. This process is often used to attach a tree that is a good bearer of fruit to another that has strong roots, combining the best qualities of two plants. It can also be used to have different but related kinds of fruit growing on the same tree. The graft in the picture has been made by cutting a slit into the stem of the host tree and putting a stem from another tree into the slit.
Hovercraft are vehicles that are supported by a cushion of air, and move forward by fans or propellers. They have fans that push air underneath them, and the air cushion is held in place by a flexible skirt around the base of the hovercraft. Hovercraft can travel over any relatively flat surface, like water, ice, swamp and dry land.
A raft is the most simple form of boat. Rafts can be made from anything that will float. The raft in the picture is a purpose-made inflatable raft.