Read the passage from "Zero-Gravity Nutrition.” How can a tiny crumb be an enemy? A crumb may be small but can turn into a big problem in space. A crumb could float and land in an astronaut’s eye. Or it could get stuck in an air vent. It’s the job of food scientists to think about crumbs and other obstacles. They come up with solutions for how astronauts can eat.

Which best states the central idea of the passage?

a)Astronauts get hungry in space just like they do on Earth.
b)Feeding astronauts in space is challenging.
c)Astronauts eat in space while they are weightless.
d)Making food for astronauts is a food scientist’s job.