Regarding the economy, consider the economic concept of scarcity – the limited availability of a product that may be in demand in the market. Consider and state why a product that is used every day by millions (for example, toilet paper or toothpaste) might suddenly be unavailable. Provide two possible reasons. And explain how scarcity impacts demand for a product

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.