Which of the following best explains the type of succession that occurred on Mt. St. Helens after the blast along with evidence to support this choice? Question 3 options:

Secondary Succession because the pocket gophers and black cottonwood survived the blast.

Primary Succession because the land appeared barren, no soil. The ecosystem counted on the tree roots that did survive to break through and spread some seeds to help with regrowth.

Primary Succession because it took about 40 years to completely recover and that is the timeframe that is typical for an ecosystem to recover from something as severe as a volcanic eruption.

Secondary Succession: The soil was able to stay intact and animals survived, so it didn't take too much time for the ecosystem to bounce back to normal.