Observe a seed's structure and explain that a seed starts a new plant similar to its parent.
Plants have "babies" too, in a way -- they are called seeds. A seed holds everything a brand-new plant needs to begin growing: a tiny plant already curled up inside, plus a bit of stored food to get it started.
Just like baby animals resemble their parents, a plant grown from a seed grows up to look like the parent plant that made the seed. An apple seed grows into an apple tree, never anything else.
Mastery looks like: They open a seed, correctly identify the tiny plant and stored food inside, and explain that it will grow into the same kind of plant as its parent.
Common stumbles: Expecting the tiny plant inside to already look fully grown; thinking a seed could grow into a different kind of plant than its parent.