A researcher is studying the conditions under which commercially raised shrimp reach maximum weight gain. Two water temperatures (25 degrees, 35 degrees) and four water salinity levels (10%, 20%, 30%, 40%) are selected for study. Shrimp are raised in containers with specified water temperatures and salinity levels. The weight gain of the shrimp in each container is recorded after a six-week study period. a) Identify the response variable. b) Identify the explanatory variables in the experiment. c) List the treatment for the experiment.