Which property of a sound wave does your ear understand as pitch?

1. A bird chirp sounds high and a lion roar sounds low. 2. The frequency of a sound wave is what your ear understands as pitch. 3. A higher frequency gives a higher pitch and a lower frequency gives a lower pitch. 4. The amplitude sets how loud the sound is, not how high or low it sounds. _Source: Siyavula Physical Sciences Grade 10 (Everything Science, CC BY 4.0), Chapter 10: Sound_