A whole or part question will always be posed on intervals. A good understanding of intervals is also needed for answering questions on transposition, chords and cadences.
You need a good understanding of scales (keys) in order to understand intervals, since to describe the interval correctly and fully you need to know the major and minor scales based on the lower note of the interval.
3
Intervals
2. Describe fully each of the numbered melodic intervals (e.g. major 2nd)