(1) The number of samples extracted from the meaning of the question is 120.3 = 40.

∴ ① Should be filled in: 40× 0.025 = 1.

② Fill in: 440 = 0. 100,

③ Fill in: 1.

So the answer is: 1, 0. 100, 1.

(2) The frequency distribution histogram is as follows: