Plzzz . i think it is aselect the noun phrase to complete the sentence. before europeans arrived, the american plains a. herds of shaggy, thunder- hooved buffalos b. many creatures filled the american skies and c. no records were kept of the species that d. there were none of the wild horses who later

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.