Here are the answers to your questions:
Question 27
Most melodies have smaller sub-sections called phrases.
Option A
True
Question 27
Melodies are also composed of motives.
Option A
True
Question 28
The triad is a chord that has four pitches.
Option A
False (A triad consists of three pitches.)
Question 29
The most important pitch of a key is its tonic, that is, the note from which the other pitches are derived.
Option B
True
Question 30
Accidentals are notes that are not played on purpose.
Option B
False (Accidentals are used intentionally to alter the pitch of a note.)