Can someone help me on this question

After first arriving in new york, charlie parker took a job as a dishwasher at jimmy's chicken shack, where played the piano nightly. listening to his astonishing harmonic restructuring, virtuoso phrasing, and breakneck tempos every night for three months, charlie parker challenged himself to adopt these qualities into his playing, and he continued to practice tirelessly.

What does it mean to have a bias (for example your bias of bts)?

Portraits are considered extremely important in early history because they were ?