Final answer:
The complementary DNA strand to A T C C G C A T is T A G G C G T A, adhering to the base pairing rules where A pairs with T and C pairs with G.
Step-by-step explanation:
If one strand of the DNA reads: A T C C G C A T, the complementary strand will read T A G G C G T A. This is because DNA strands are antiparallel, and the base pairing rules stipulate that adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). So, each base on the original strand dictates the corresponding base on the complementary strand due to these pairing rules.