I mean, there's plenty of differences between muscle and nerve cells. For one, they serve different functions. Nerve cells react and send stimuli rapidly through action potentials, functioning in the nervous system and allowing the brain to communicate with the rest of the body, while muscle cells allow muscles to move. Another difference is the structure of the cells, with nerve cells having dendrites, axons, and neurotransmitters to assist in the firing of action potentials. You're going to have to be a little more specific, I can't really help you any more with such a broad question.
Decomposers is the correct answer
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.