Texture makes Mona Lisa look realistic, her hair, skin, and dress all use texture, or the illusion of texture with complex shading, blending, and highlights.
Space is used to bring attention to Mona Lisa’s frame, placing her in front of a far off background. She's placed in the center of a balanced background. also using value to bring your attention to the contrast of her dark dress and light skin. The light background is meant to balance out the darkness of her dress and hair.