Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

You call egg-shaped galaxies, which are reddish to yellowish in color because they contain mostly old stars, elliptical galaxies.
What do you call egg-shaped galaxies, which are reddish to yellowish in color because they contain mostly old stars?

Zero is the net force acting on an object when two equal forces are applied from opposite directions.
What is the net force acting on an object when two equal forces are applied from opposite directions?

One gram of carbohydrates provides four calories of energy.

One gram of carbohydrates provides how many calories of energy?