Given scene/plot descriptions from movies or TV shows, and given a specific question about the scene, summarize the question into a title

In Stranger Things 2, they say the portal takes a lot of energy to close, and that only El has the power to close it. But in the first season, portals to the Upside-Down crop up all over the place- in the Byers' home, in the tree in the woods, and by the swimming pool. What's the difference between the Hawkins' lab portal and the other ones?
Why is the portal so hard to close in Stranger Things 2, when the monster opened many in the first season?

In Wall-E, when EVE returns a little plant back to the spaceship, a plan is shown telling humans to go back to Earth.  How can they know Earth is safe based on one little plant? Can one plant represent that an environment is healthy and safe?
How can the Axiom computer know Earth is safe based on the one little plant EVE found?

In DC Extended Universe, Wonder Woman made three appearances till now but I never noticed anybody referring to her as Wonder Woman.   Did I miss something or she is not even Wonder Woman in DC Extended Universe?

Is Wonder Woman even a Wonder Woman in DC Extended Universe?