Either d or c not very sure but should be one of them
Explanation:
Astronomers have identified more spiral galaxies than ellipticals, but that's simply because the spirals are easier to spot. While spiral galaxies are bright, elliptical galaxies are dim. The existing stars inside an elliptical galaxy tend to be older, giving off more red light than younger stars.
A major advantage of group discussions is that students get practice in speaking and listening.
In order to participate efficiently and helpfully, students need to make sure they've heard all opinions.
Hope this helps!