Which of the following situations is most likely to cause positive stress?

If something is painful during exercise, what should you do? a. back off the exercise. b. modify the exercise. c. consult a physician if the pain persists. d. all of the above

You isolate an infectious substance capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. you have four methods at your disposal to analyze the substance and determine the nature of the infectious agent. i. treat the substance with enzymes that destroy all nucleic acids and then determine whether the substance is still infectious. ii. microscope. iii. culture the substance on nutritive medium, away from any plant cells. iv. treat the sample with proteases that digest all proteins and then determining whether the substance is still infectious. if you already know that the infectious agent was either bacterial or viral, which method(s) listed above would allow you to distinguish between these two possibilities? a) ib) iic) ii or iiid) iv

Scientists believe that differences in cause hot, plastic-like rock in the asthenosphere to rise toward earth's surface. a. density c. weight b. magnetism d. composition select the best answer from the choices provided