ACT真題每日一練11.16
Depth (cm) |
Temperature (oC) |
pH | Concentration in sediment (ppm) | |||||
SO42– | S2– | CO2 | Fe3+ | Fe2+ | O2 | |||
0 | 4 | 7.0 | 7.0 | 0.0 | 1.0 | 4.0 | 0.5 | 2.0 |
5 | 5 | 6.5 | 5.0 | 2.0 | 1.5 | 3.0 | 1.5 | 1.0 |
10 | 7 | 6.0 | 3.5 | 3.5 | 2.0 | 2.0 | 2.0 | 0.0 |
15 | 9 | 5.5 | 3.3 | 3.8 | 3.0 | 0.8 | 3.8 | 0.0 |
20 | 10 | 5.0 | 3.0 | 4.0 | 1.0 | 0.5 | 4.0 | 0.0 |
Table adapted from R.M. Atlas and R. Bartha, Microbial Ecology: Fundamentals and Applications.
©1981 by Addison-Wesley Publishing Company.
According to the information provided in the table, the concentration of which of the following ions and dissolved gases is constant for sediment depths of 10 cm or more?
A. Sulfide (S2–)
B. Carbon dioxide (CO2)
C. Ferric iron (Fe3+)
D. Oxygen (O2)