Answer:
The mRNA sequence that complements the DNA sequence GATCAC is CUAGUG.
Explanation:
A is adenine, which in DNA, pairs up with Thymine.
In mRNA, A pairs up with U, Uracil. Uracil is simply Thymine's replacement in mRNA.
In both mRNA and regular RNA, G, Guanine, and C, cytosine, always pairs up.
To find the sequence, I followed the sequence, but just switched it up with its pairs, getting CUAGUG from GATCAC.
Hope this helped and good luck :)