If the bases on one strand of dna reads ttacgcg, what would be the complementary strand?

AATGCGC

Explanation:

A(adenine) and T (thymine) are opposites, wherever T is the complimentary will be A and vise versa. The same goes for C (cytosine) and G (guanine). {Remember that if the strand is RNA T will be substitued for U (Uracil).}

*If you are an AP Biology student make sure you understand which end is 3' and which is 5', the complimentary strand will run the opposite direction.