I believe it is nervous tissue
You end up with a polyploid condition. Not uncommon in organisms, especially plants, like angiosperms.
Look up "polyploidy".
Polymerization would be the answer you're looking for.
Answer:
AAATT - TTTAA
CGCAT - GCGTA
GGGAC - CCCTG
ACGGT - TGCCA
Explanation:
In DNA, A and T, also known as adenine and thymine pair together and G and C, also known as guanine and cytosine pair together due to the hydrogen bonds formed between the two bases.