Read the passage. Then answer the question.
Stars provide light to the planets that orbit them. Yet there's a cosmic twist. These stars can run out of hydrogen in their core. It happens over time. This causes them to expand and become red giants. As red giants grow, they swallow the planets closest to them.
Scientists call this planetary engulfment. And they think it's pretty common. Ready to book a flight to Mars? Hold off. There's still a lot to learn about this phenomenon. Still nervous? This might help: Earth's sun has plenty of hydrogen in its core. It should keep shining as is for another 5 billion years.
Which three details would be most important in a summary of this paragraph?
A.Stars expand over time as they run out of hydrogen in their core.
B.Scientists are still learning how planetary engulfment works.
C.Red giants sometimes swallow the planets closest to them.
D.There are things that scientists are still learning about the universe.
E.Some people are interested in taking a trip to Mars one day.
A. Stars expand over time as they run out of hydrogen in their core.
B. Scientists are still learning how planetary engulfment works.
C. Red giants sometimes swallow the planets closest to them.