Salt is notoriously dangerous to land snails; however, some populations of aquatic, freshwater snail have brackish (or a mix of salt and fresh water) water adaptations and live in different parts of a river system. A group of scientists monitored salt concentrations in the habitats of two freshwater snail populations located nearby and recorded the data as follows (in ppt, parts per thousand): Population 1 (Day 1): 0.1 ppt (morning), 0.0 ppt (afternoon), 0.1 ppt (evening) Population 2 (Day 1): 0.3 ppt (morning), 0.5 ppt (afternoon), 0.2 ppt (evening) In 3–5 sentences, 1) describe how these results show why the brackish water adaptation may be necessary, and 2) explain how to determine whether the inherited adaptation is influenced by environmental factors.