To test the quality of water sources in her area, Shameka collects five samples from each water source and tests the quality of each sample. Which important step of scientific design is Shameka conducting? and do not say c cause it is not thank you please hurry

The small molecule cyclic amp (camp) takes about 0.2 second to diffuse 10 μm, on average, in a cell. suppose that camp is produced near the plasma membrane on one end of the cell; how long will it take for this camp to diffuse through the cytosol and reach the opposite end of a very large cell, on average? assume that the cell is 200 μm in diameter.