I'm studying biology for the first time seriously. I've been reading OpenStax College's material. In the section of "The Cell Membrane", I have the following problem:
Choose the answer that best completes the following analogy: Diffusion is to ________ as endocytosis is to ________.
- filtration; phagocytosis
- osmosis; pinocytosis
- solutes; fluid
- gradient; chemical energy
I chose number 1, but the site says the correct answer is number 2. Could someone please explain why?
[EDIT]
I chose number 1, because diffusion and filtration were passive ways to transport, while endocytosis and phagocytosis are active. I didn't not take in to account that 2. fitted better, because the osmosis part was confusing me.