Answer
Si could potentially form the same kind of complicated structures as C since it is in the same column of the periodic table as C and thus has the same number of valence electrons. However, since it is in a different row, it might have enough differences from C to not be able to as useful for life as C.
Work Step by Step
From Figure 2.7, Si is more abundant than C, yet one does not hear of it being involved in making complex molecules in living things. Having C and Si in the same column of the periodic table implies similar chemistry, but the difference in row implies some important differences which might be the reason why life is not based on Si, in spite of its great abundance.
