Question

the diagram below shows a portion of a double - stranded dna molecule. the letters in the diagram represent the four bases adenine (a), thymine (t), guanine (g), and cytosine (c)
which sequence of bases do the question marks represent?
a cac
b ct - c
c gac
d cuc

Explanation:

Step1: Recall base - pairing rules

In DNA, adenine (A) pairs with thymine (T) (by two hydrogen bonds), and guanine (G) pairs with cytosine (C) (by three hydrogen bonds).

Step2: Analyze each position

• For the first question - mark (paired with C): Since G pairs with C, the base is G.
• For the second question - mark (paired with T): Since A pairs with T, the base is A.
• For the third question - mark (paired with G): Since C pairs with G, the base is C.

The sequence of bases is G - A - C.

Answer:

C. GAC