Choose an organism and predict a trait that would be helpful for its survival. Do you think this could be an evolutionary change? What would have to happen for this trait to be expressed?

Which of the organisms listed below performs nitrogen fixation? a. legumes b. plants c. bacteria d. fungi

Imagine a self-reactive t cell that has not undergone clonal deletion in the thymus (that is to say, it has escaped central tolerance). if it encounters self antigen in the absence of an infection or inflammation, what will happen to this self-reactive t cell? (select two answers) (a) the t cell undergoes clonal expansion. (b) the t cell gains effector functions. (c) the t cell undergoes apoptosis. (d) the t cell becomes activated. (e) the t cell becomes anergic.

Which of the following correctly matches an immune system cell with the defense it produces? a. b cells release cytotoxins. b. t cells release cytotoxins. c. b cells absorb antibodies. d. t cells absorb antibodies.