yes
There are decagons which will tessellate.
Yes.
By itself, it will never tessellate.
yes it can because it will have all the same side and it will cover you entire paper
Polygons that when joined together leaving no gaps or overlaps are said to tessellate with each other such as triangles, 4 sided quadrilaterals and hexagons to name but a few.
No. Tessellations require straight edges from which the geometric shape can flip, or along which the plane figure can slide. The answer is only partially correct. Circles cannot tessellate, but as a study of some of the works by M C Escher will show, straight lines are not necessary.