You water three sunflower plants with salt water. Each plant receives a different concentration of salt solutions. A fourth plant receives pure water. After a two-week period, the height is measured. i think the indepent variable is sunflower ... variable is height measured and the control variable is the fourth plant.
The answer would be the chloroplast. The cell wall mainly covers and protects the cell's insides.
Answer:
I looked it up and the answer is fluid mosaic.
