Final answer:
The passage from "The Race to Space: Countdown to Liftoff" introduces a problem: the venting of gas from the Apollo 13 spacecraft.
Step-by-step explanation:
The passage from "The Race to Space: Countdown to Liftoff" introduces a problem. The authors describe the astronauts relaying information to Mission Control about what they were seeing and the crew on the ground trying to figure out the cause of the problem.
When astronaut Jim Lovell looked out the cockpit window, he saw that the Apollo 13 spacecraft was venting gas into space. This problem is the main focus of the passage and sets the stage for the rest of the story.