Final answer:
The DNA strand that is used for transcription to mRNA is known as the template strand, which directs the synthesis of mRNA by complementing its sequence.
Step-by-step explanation:
The strand of DNA that gets transcribed to mRNA is called the template strand. During the process of transcription, this template strand serves as a guide for creating a complementary RNA sequence. In contrast, the other DNA strand, which has a sequence similar to the mRNA except that it contains thymine (T) instead of uracil (U), is known as the coding strand or the sense strand. The mRNA mirrors the sequence of the sense strand with the substitution of U for T.