The driving force for mass transfer by molecular diffusion is the difference in
This outcome reflects core biological organization, where structure-function relationships govern cellular processes. Option D captures this correctly because it integrates fundamental life science principles, consistent with textbook descriptions and experimental observations in general biology.
Ref: Campbell et al., Biology, 11th Edition, Chapter 2, Chemical Basis of Life, discusses fundamental biological principles, molecular organization, cellular structure and metabolic processes providing broad foundation for life sciences understanding and integration.