This activity explores an image of tattoo ink particles inside cells, which serves as a phenomenon for learning about the structure and color of human skin.

This activity builds on information presented in the video Selection for Tuskless Elephants. Students use scientific evidence and reasoning to construct an explanation of and develop an argument for tusklessness in elephant populations.

This interactive module allows students and educators to build models that explain how the Earth system works. The Click & Learn can be used to show how Earth is affected by human activities and natural phenomena.

This activity allows students to formulate and analyze scientific questions.

This animation shows how mutations in an ion channel protein lead to the genetic disease cystic fibrosis. The animation also discusses how research on this protein has been used to develop treatments for the disease.

This hands-on activity engages students in asking questions about phenomena using collections of images.

This activity explores images of animals that live in groups, which serve as phenomena for learning about animal behavior.

In this activity, students collect and analyze evidence for each of the major conditions for evolution by natural selection to develop an explanation for how populations change over time.

This activity explores images of plant cells and structures, which serve as phenomena for learning about how plants respond to stimuli.

This interactive module explores biomes, climate, biodiversity, and human impacts around the globe and at different times.

This video follows scientists working in Bangladesh as they test fruit bat populations to determine whether they are infected with Nipah virus, a potentially deadly human pathogen.

This activity explores images of chalk formations and coccolithophores, which serve as phenomena for learning about the interactions between biological and geological processes.