The chloroplast<br/>internal membrane is organized into flattened membranous sacs called<br/>_________; they, in turn, are arranged in orderly stacks called<br/>_______ that contain energy-transducing machinery. ( ) A: thylakoids, grana B: grana, thylakoids C: thylakoids, stroma thylakoids D: thylakoids, grana thylakoids

The flattened stacks of saclike structures in the chloroplast are called grana,Each sac is known as( ) A: a lumen B: a granum C: a membrane D: a thylakoid E: a photoreactive cente