After she saw the shark, jen clambered back into the boat as quickly as she could. what does clamber mean? walk lazily jump gracefully climb awkwardly scream fearfully

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.