What is the differencve between single phase power and three phase power?

Two phases. :D

Actually most homes have just single phase. Many commercial businesses have 3 phase. What is your question?

Sounds like a class question and if it is the answer is in your books or on Google.

2=two,, 3 minus 1=2

the 3 phases are 120 degrees apart, 3 x 120= 360 degrees (one rotation of a motor/generator)

single phase power is actually two phases of power that are 180 degrees out of phase, to equal the 360 degrees

as stated above, 3phase is usually used in larger buildings, and single phase is used in light commercial and residential applications.
this is probably useless information!