ogy even though we’ve never directly detected dark matter? How can we rule out stellar remnants (ie black holes and pulsars) from being DM candidates?…

Why do we need to have dark matter in our cosmology even though we’ve never directly detected dark matter?

How can we rule out stellar remnants (ie black holes and pulsars) from being DM candidates?

How was dark energy "discovered"?

What is the horizon problem and how does inflation solve it?

Explain how the "top-down" scenario for the formation of structure (e.g. galaxies, clusters of galaxies) in the Universe differs from the "bottom-up" scenario.