Which statement about the use of independent variables in controlled experiments is correct? 1.
A different independent variable must be used each time an experiment is repeated.
2.
The independent variables must involve time.
3.
Only one independent variable is used for each experiment.
4.
The independent variables state the problem being tested.

The moths will eventually become extinct

The need activity of the nurse is to suction discharges from the trachea. current treatment approaches in the pressing consideration facilities or crisis offices are corticosteroids and nebulized epinephrine; steroids have demonstrated advantageous in extreme, direct, and even gentle croup. in the clear instances of croup, anti-microbials are not endorsed, as the etiology is viral