Given the dna strand gaattcctcgag, what would be the complimentary strand to make the double stranded dna? how do you get the answer?

What can be found in every skeletal muscle? a. nerves, bones, cartilage, and connective tissue b. tendons, cartilage, nerves, and blood vessels c. muscle fibers, nerves, connective tissue, and blood vessels d. tendons, nerves, blood vessels, and bones

Can someone i have no idea of how to do this.

The distant ancestors of tigers may have had bodies without stripes. use the theory of natural selection to explain how tigers may have evolved to have stripes.