What is the prediction of the CAPM with respect to the expected return on any security? 

Why is the variance of a portfolio of internationally diversified stocks likely to be lower than the variance of a portfolio of U.S. stocks? 

 Assuming that the expected yen return on the Nikkei 225 index is 5%, and its volatility is 18%, and the volatility of the euro/yen exchange rate is 9%, what is the volatility of the euro return on the Nikkei 225 index if the correlation between the Nikkei index's return in yen and changes in the euro/yen exchange rate is 0.15?