Please answer as much as possible, thank you!

3. The dose-response (lethal) curve for three toxicants is shown below. a) For each toxicant, identify the IDso. b) Which toxicant ( A,B, or C) is a carcinogen? And why? 4. Based on a 106 risk for a 70kg individual consuming 2L of water per day, the DWEL for a contaminant is 10g/L. What potency would produce this value? 5. The pesticide chlordane enters a lake at an annual rate of 1000kg/ year due to runoff. The lake has a volume of 108m3 and a flow-through rate of 107m3/ year. Upstream river water has a chlordane concentration of 0.01mg/L. While chlordane is not biodegraded, it adsorbs strongly to suspended solids and is removed by sedimentation with a net rate of 0.0015/ day. Fish in the lake are exposed to the chlordane in the water and accumulate some in their tissues. What is the expected chlordane concentration in the fish tissue (mg chlordane/kg fish)? You may assume that the processes are at steady state