PDF Third Grade Science PLANTS PLANT LIFE CYCLE: #2 2. From the seed, a tiny new plant, called a seedling, grows. You will notice roots, a curled stem and very small leaves. Fill in your sequencing sheet: PLANT LIFE CYCLE: #3 3. Then roots grow down into the soil and the stem uncurls upward. leaves get bigger. YOUNG ADULT PLANT LIFE CYCLE: #4 4.