What are the primary variables that influence the risk of a portfolio of assets?

According to me the elements that have an impact on the risk of a portfolio are :

1) The correlation of the assets

2) The standard deviation of the asset itself (risk of asset)

3) The weight of the different assets in the portfolio.

The answer on the website suggests that it is:

The maturity, default, seniority and marketability risk but according to me this has an impact on the risk premium from an asset.

Could someone help me out? Kind regards,