How can we use the CAPM to estimate a firms cost of capital? What is the twin method? Why do we need to unlever a firms beta?

What is an asset, equity, and debt beta? How does it related to the expected returns on these assets and the cost of capital?

Why is equity at-least-as-risky/riskier than debt? Why is equity at-least-as-risky/riskier than owning the firms assets?

What is the Modigliani and Miller theorem? Under what conditions does it hold? Why are these conditions useful to know in real life when we know they are violated? Why is M&M such an important theorem? How does the M&M view differ from the traditionalists?

What happens to the cost of equity as a firm levers up? How does this affect the weighted average cost of capital?