A student is instructed to record the odor of a substance after heating it in a test tube. Which is the correct safety procedure for the student to follow?
A Wave the fumes from the test tube toward the nose with a hand and inhale
B. Tilt the test tube toward the nose and inhale
C. Place the test tube directly under the nose and inhale
D. Cup hands over the test tube and inhale

18. over time, how do sand dunes tend to migrate? a. perpendicular to the movement of the wind b. in the same direction as the wind blows c. toward the wind d. in random directions

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.

The term facultative anaerobe refers to an organism that