paragraph 3
A rule is generally more specific if it applies to a fewer number of elements than another rule that encompasses those elements. The more facets a rule has the more specific it is. When pseudo-classes are applied this is more specific than without the pseudo-class. For example, p:hover will win over just p.
paragraph 4
Contextual selection is more specific because it scopes the rule to elements within a certain subset of those on the page. For example, a rule that applies to all the paragraphs within articles is more specific than a rule that applies to all the paragraphs on the page. IDs are most specific because you are directly applying them to the desired HTML element. The rule based on an ID will always win over other rules