What is the complementary sequence to the dna strand 5' tgacgtgat 3'?

The answer is : actgcacta

This DNA template is written 5' to 3', just like it's supposed to be. The complementary strand also needs to be that way.

5' tgacgtgat 3'          the direction (--->)
3' actgcacta 5'          the direction (<---)

adenine (A) will bind with thymine (T) and guanine (G) will bond with cytosine (C).

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