Select the statements about the K-T boundary that are true.
- The K-T boundary in Zumaia, Spain is sharp--representing an abrupt change in the marine ecosystem.
- The K-T boundary separates rock layers of the Cretaceous period from those of the Tertiary period.
- The K-T boundary dates to 65 million years ago (when the dinosaurs disappeared).
- The K-T boundary is a layer of debris ranging from large chunks of fractured rock to thin clay deposits and it is found in many different parts of the world. It separates rock layers from the end of the Cretaceous period from those beginning of the Tertiary period. It coincides with an abrupt loss of biodiversity.

Where does all the water go? according to the environmental protection agency (epa), in a typical wetland environment, 39% of the water is outflow; 46% is seepage; 7% evaporates; and 8% remains as water volume in the ecosystem (reference: united states environmental protection agency case studies report 832-r-93-005). chloride compounds as residuals from residential areas are a problem for wetlands. suppose that in a particular wetland environment the following concentrations (mg/l) of chloride compounds were found: outflow, 60.4; seepage, 73.7; remaining due to evaporation, 26.4; in the water volume, 46.8. (a) compute the weighted average of chlorine compound concentration (mg/l) for this ecological system. (round your answer to one decimal place.) mg/l (b) suppose the epa has established an average chlorine compound concentration target of no more than 58 mg/l. does this wetlands system meet the target standard for chlorine compound concentration? yes. the average chlorine compound concentration (mg/l) is too high. yes. the average chlorine compound concentration (mg/l) is lower than the target. no. the average chlorine compound concentration (mg/l) is lower than the target. no. the average chlorine compound concentration (mg/l) is too high.