For aquatic ecosystems, these factors include light levels, water flow rate, temperature, dissolved oxygen, acidity (pH), salinity and depth. (Light level is an important factor in aquatic ecosystems.)
The correct answer will stress the differences between the observational study and experimental study - and options a), c) and d) can be true of both.
The correct answer is:
b. Experimental subjects are left free of manipulation
-this is the major difference between the observation and experiment.
If Madison has a difficulty in checking fine details she then has a problem in visual acuity. This means the clearness of a vision. This is the function of the retina. Hope this is the answer and would be of help.
