Everybody is different. Look at the people around you. What do you see? You might see people of different ages. Maybe they are all different heights. Are they wearing different clothes and different shoes? Some might be boys, and others might be girls. Some might have different skin color. No two people are exactly the same.
Differences can lead to bad things happening sometimes. Some people pick on others because of all kinds of differences. People are picked on because of their size. Some people are picked on because of their age. Some people are picked on because of the clothes they wear. Some people are picked on because of the color of their skin.
Many years ago, there was a teenager who loved to play baseball. His name was Henry Aaron, but most people called him "Hank." He was born in Alabama in 1934. He learned to be a very good baseball player in school. At the time, he wasn't allowed to play in major league baseball because of his skin color. Hank is an African-American.