Even numbered intervals mix lines and spaces on the staff. ?

Question

Even numbered intervals mix lines and spaces on the staff.

t/f

??

Answer 1

True.

Imagine a middle C on the treble clef, which is a line note.

Going to D is a second, and is a space note.

Going to F is a fourth, and is a space note.

Going to A is a sixth and is a space note.

Going to treble C is an octave, and it is also a space note. Those intervals start on a line and end on a space, or start on a space and end on a line.