Seeds have baby plants in them, so they grow sort of like babies before they're born. The seeds of flowering plants even grow inside the plant's ovary, and then a fruits form around them. The seeds of other plants grow inside pine cones. Both kinds of seeds have the embryo of the baby plant inside them. Here is a good link, from searching this - seeds baby plants :

Keep asking questions! You can search for answers on the internet at google.com, or you can look in Wikipedia.com on the internet - or in Simple English Wikipedia (simple.wikipedia.org). But sometimes you'll find wrong answers on the internet, too, so keep your mind open to new ideas and new answers.