Okay kiddo, imagine your body is like a puzzle that has tiny pieces called genes. Sometimes these genes can be a little different between different people, like you might have blue eyes and your friend might have brown eyes. These differences are called variations or SNPs (pronounced "snips").
Scientists use something called a SNP array to look at millions of these variations all at once. It's kind of like looking at a bunch of different puzzles all at once to see which pieces are different. This SNP array helps scientists understand how these tiny differences might affect things like your health or how certain medicines might work for you.
It's like having a really cool tool to help scientists solve puzzles about the human body!