Answer: 4
There are 4 significant figures in 7.030
The zeros in this case are significant. Even the zero at the end is significant.
If a zero is between two nonzero digits, then that zero is significant. If a zero is to the right of a decimal point and to the right of a nonzero digit, then that zero is significant. This will mean something like 7.0300 has 5 sig figs and 7.03000 has 6 sig figs, and so on.
