Welcome to Art!
Abstract art can show something from the real world (like a face or flower) or it can be a composition using shapes, line, colors, and other elements of art. Artists may make abstract art to express ideas and feelings, or to experiment.
Realistic art looks (mostly) like a real person. place, object or other motif seen in the world around us. What makes a drawing or painting look realistc?
Sometimes artists depict "real" subject matter like faces, animals, or places in a way that breaks from realism. The artist changes the colors, lines, and other details from those we'd see in real life.
In some abstract artwork, we see shapes and lines and color. We can't recognize any objects we see in real life. The artist may be expressing a mood or message without showing nameable objects.