A person with type blood is able to donate to anyone because their blood .

A; lacks B antigens
B; lacks A antigens
O; lacks any antigens
AB; contains both A and B antigens

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.