This column focuses on promoting learning through assessment. This month's issue explores structure and function as it relates to animals and plants. One of the disciplinary core ideas in "A Framework for K-12 Science Education" is LS1.A Structure and Function (NRC 2012). This disciplinary core idea is included in the "Next Generation Science Standards" (NGSS), which state that grade 1 students are expected to use the idea that "all organisms have external parts. Different animals use their body parts in different ways to see, hear, grasp objects, protect themselves, move from place to place, and seek, find, and take in food, water, and air. Plants also have different parts (roots, stems, leaves, flowers, fruits) that help them survive and grow" (NGSS Lead States 2013, p. 12). The formative assessment probe "Is It Made of Parts?" is designed to uncover K-2 children's initial ideas about the parts of organisms. The teacher can then use this assessment information to make informed decisions about scaffolding the instructional opportunities children will need to develop a foundational understanding of the relationship between structure and function.