Passage I

Two measures of water quality are the number of Escherichia coli bacteria present and the biotic index, BI (a numerical value based on the type，diversity, and pollution tolerance of aquatic invertebrate animals). Both of these measures can be affected-by water flow.

E.coli levels that are above 100 colonies formed per 100 mL of water indicate reduced water quality. Figure 1 shows the E. coli levels on 5 collection days at Sites l and 2 in a river.

Table 1 shows how water quality rating varies with BI. Table 2 shows the average BI of each site during the collection period.

Figure 2 shows the water flow at each site on the 5 collection days.

3. As water quality improves, the number of stone fly larvae (a type of aquatic invertebrate) increases. Students hypothesized that more stone fly larvae would be found at Site 1 than at Site 2. Are the data presented in Table 2 consistent with this hypothesis?

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

From table 2, it can be seen that the BI of Site 1 is larger, which means that the water quality of Site 1 is better, so it can be speculated that Site 1 will indeed have more stone fly larvae