#### Answer

(a) 5
(b) 1
(c) 3
(d) 3

#### Work Step by Step

(a) In 1.5003, all nonzero digits are significant as well as the two zeros between the nonzero digits. Therefore, there are five significant figures in this number.
(b) In 0.007, there is only one significant figure: the 7. Leading zeros are not significant.
(c) In 5.70, there are three significant figures. The trailing zero is also significant.
(d) In 2.00 x 10$^7$, there are three significant figures. Because the number is written with scientific notation, figuring out the significant figures is simple. The 2 is significant as well as the two trailing zeros.