Question

A hummingbird’s cells use oxygen to produce the ATP needed to move its wings. How does the oxygen enter these cells? (1 point) Responses diffusion diffusion active transport active transport passive transport passive transport receptor mediated endocytosis

Answer 1

Diffusion — specifically simple (passive) diffusion. O2 is small and nonpolar, so it crosses the cell membrane down its concentration/partial pressure gradient without using energy.