Why is ongoing star formation typically negligible in elliptical galaxies compared to spiral galaxies?

Answer

They contain very little cold, neutral gas and dust.

The lack of star formation is due to the scarcity of cold, neutral gas and dust, the necessary raw materials; the remaining interstellar medium is usually hot and ionized.

Why is ongoing star formation typically negligible in elliptical galaxies compared to spiral galaxies?
Spacegalaxiesastronomystructureelliptical galaxiesgalaxy classificationelliptical