In grade one, students engage with plants, animals, light and sound to recognize more patterns in the world around them. All of the instructional segments in grade one set up future learning: What causes plants and animals to look different from one another but similar to their parents? How does light allow our eyes to see things? What causes the phases of the moon and the seasons? None of these questions will be answered at this grade level, but the CA NGSS learning progression will revisit them repeatedly in later grades. The purpose of first grade is to give students a common background experience with these phenomena and have students observe them well enough to recognize patterns that prompt them to start asking questions about cause and effect relationships.

(CA-NGSS Framework, Chapter 3, 2016)