2.( 1) The growth height of bean sprouts increases with the increase of days, and the increasing speed is faster and faster.

(2) 5.5-0.5 = 4cm5/(5-1) =1.25cm.

The average daily growth of bean sprouts is 1.25cm.

(3) 5.5+2+2 = 9.5cm

By the seventh day, the height of bean sprouts is about 9.5 cm.