The disc which contains spiral arms of the galaxy part would be used to study the birth starts in a spiral galaxy
Explanation:
A galaxy has four parts and they are bulge, disc, spiral arms and halo
Bulge primarily contains old stars, gas and dust.
The disc contains the spiral arms also, it is the flattened portion of the spiral arms where we could find most of the young stars, gas and dust. Some old stars are also found in this region
Spiral arms are only found in spiral galaxies. It is the curved extension begins from the bulge. Here, also you could find young stars, dust and gas.
Halo is the part where we could find clusters or individual old starts and also the dark matter. The dark matter we can't see but can estimate the gravitational force.
