In this unit, students explore similarities and differences between young and adult plants and animals and how behavior and external parts help living things survive. Students begin by completing a card sort activity in which they use patterns of similarities and differences among living things as evidence for their sorting. Next, students observe plants and animals to determine the patterns of similarities and differences between young and adult individuals within a species. Their evidence supports the idea that young and adult plants and animals are similar but not exactly alike. Students read about how the structure of external parts of plants and animals helps living things survive.