Answer: It to activate
Explanation:Mount St. Helens, Washington, is the most active volcano in the Cascade Range. Its most recent series of eruptions began in 1980 when a large landslide and powerful explosive eruption created a large crater, and ended 6 years later after more than a dozen extrusions of lava built a dome in the crater.
It would be uracil (C)
thymine would be complementary to adenine in DNA but because it is RNA it is replaced by uracil.