This is a slide of human cheek cells. After scraping the inside of their mouths, students in Ms. Gordon's class smeared the swab on a slide and stained them blue. These cells are parts of a large, complex organism, a human. But these cells. like the other cells in the human body all have an important organelle, seen here. It stains dark blue and is the control center of the cell. What is this organelle? A) DNA B) cytoplasm C) membrane D) nucleus