4-4 Sentence Completion. Complete each of the following state- ments about cellular structure in ten words or less. (b) When placed in a glass of water, a dried date . . 4-5 Telling Them Apart. Suggest a way to distinguish between the two elements in each of the following pairs. (a) Plant peroxisomes; thylakoids d) Smooth ER; mitochondria (e) Vacuole; nucleus .