You are constucting concentration-response curves using an isolated tissue preparation set up in a 20 ml organ bath. You have access to a 20- 200 l automatic pipette and are given a series of 10-fold dilutions of the agonist from 10-2M to 10.5M. You are using the cumulative method of drug addition and need to work out the additions to achieve the required bath concentrations of the drug. Which of the following would you add to achieve an initial bath concentration of 1 x 108M. Select one: a. 20l of a 1 x 10-4M solution b. 20l of a 1 x 10 5M solution c. 20l of a 1 x 10-6M solution d. 20l of a 1 x 10-7M solution e. 20l of a 1 x 10-M solution Once you have got the response to 1 x 10-8M, what would your next addition be to achieve a bath concentration of 3 x 108M? Select one: a. 60l of 1x10.5M b. 20l of 1x10.5M c. 40l of 1x10-5M You have seen the response to 3 x 108M and are now going to test the response to 1 x 10-7M. Which of the following would you add? Select one: a. 20l of 1x10-4M X 140l of 1x10-5M c. 10l of 1x10 4M Od. 70l of 1x10-5M Ob.