What will a scientist NOT likely use to determine the presence and concentration of water pollutants? 

A)  computer models 
B)  satellite photographs 
C)  analysis of indicator species 
D)  chemical analysis of water samples

Satellite photographs may be useful in identifying and monitoring large-scale water issues, such as harmful algal blooms, but they would not provide precise information on the presence and concentration of specific water pollutants. A scientist would likely rely on chemical analysis of water samples and analysis of indicator species to determine the extent of water pollution. Computer models may also be useful in predicting the spread of pollutants, but they would not be sufficient on their own.