In this section, students add more organisms to their aquariums, including anacharis, duckweed, and snails. Students make careful observations of the structures of these organisms and relate structure to function. Students also begin a drawing of their aquarium, illustrating the different organisms. In addition, students investigate the process of photosynthesis and communicate their results.

Student Resources

• 3.1 Vocabulary
• 3.2 Observing Aquatic Organisms
• 3.3 Oxygen–Carbon Dioxide Cycle
• 3.4 Section 3 Assessment

Learn by Reading

For additional content-area reading, check out the Houghton Mifflin Science eBook: Grade 3, Unit B, pages 44–45.