What literary technique is used by the author to describe the snowflake

In this excerpt , mr.stonecrop is compared to a mountain. how does this description relates to mr.stoncrops roll in the main conflict of the story

1. in which sentence is the underlined portion a predicate nominative? for astronauts, going into space to repair orbiting equipment becomes a challenge. for astronauts, going into space to repair orbiting equipment becomes tricky. for astronauts, going into space to repair orbiting equipment becomes challenging. for astronauts, going into space to repair orbiting equipment becomes frequent.

What were the strengths used to persuade the audience in the speech “i have a dream” i really need on this one. i also posted a few more. can someone ?