Smooth Rough endoplasmic Nucleus endoplasmic reticulum reticulum Flagellum Not in most plant cells Lysosome Centriole Ribosomes Peroxisome Golgi apparatus Microtubule Plasma membrane Cytoskeleton Intermediate filament Microfilament Mitochondrion Copyright2003 Pearson Education,Ine..publishing as Benjamin Cummings. Humans are multicellular organisms,being composed of about 100 trillion(1014)cells.Humans are multicellular organisms, being composed of about 100 trillion (1014) cells