This animation shows how the proton gradient across the mitochondrial membrane powers the ATP synthase enzyme to make ATP. It is the third of three animations about cellular respiration.

This animation shows how the enzyme complexes of the electron transport chain harvest energy from cofactor molecules to pump protons across the mitochondrial membrane and establish a chemical gradient. It is the second of three animations about cellular respiration.

This animation shows the reactions of the citric acid cycle, which splits off carbon atoms and generates energy-rich reduced forms of cofactor molecules. It is the first of three animations about cellular respiration.

This film explores how life recovered after an asteroid wiped out the dinosaurs and how those events shaped the diversity of plants and mammals on Earth today.

This video follows biologist Shane Campbell-Staton, who is studying the adaptations that allow deer mice living at high elevations to stay warm and active during the winter.

This multipart animation series explores the process of photosynthesis and the structures that carry it out.

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

This interactive module explores the environmental factors and species involved in five major mass extinctions.

This animation illustrates the main stages of the water cycle in Gorongosa National Park, an ecosystem that experiences both wet and dry seasons.

This activity allows students to use authentic scientific data to make claims about the threat of coral bleaching for reefs around the world.

Several questions are embedded within the short film The Day the Mesozoic Died, which tells the story of the scientific quest to explain one of the greatest, long-standing scientific mysteries: the sudden disappearance of the dinosaurs at the end of the Cretaceous period.

This animated short video celebrates the early 20th-century German astronomer and atmospheric scientist Alfred Wegener, who first proposed that continents once formed a single landmass and had drifted apart.