Syntax

1- Explain the notion of the head of a phrase by analyzing the internal elements of NP, VP, AP, ADVP, and PP.

What does it mean by saying that each phrase category must contain a head, which is the name of a lexical category and every other element of the phrase category is optional, but the head is always obligatory? Provide examples wherever necessary to make your explanations clear.

2- Explain the 'structural' distinction between a complement and an adjunct with at least four different XPs to show the hierarchical internal structure of each by drawing a structural tree for each. Your example may contain a complement and an adjunct(s).