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.
Answer:
Respiratory epithelial cells line the respiratory tract from trachea to bronchi into bronchioles and alveolar sacs. ... The goblet cells produce and secrete mucous to trap pathogens and debris within the airway tract. Basal cells are progenitor cells that differentiate into cells types found within the epithelium.
