Alpha helix and beta sheets are the secondary structure of protein
Answer:D. Ratio of oxygen/nitrogen
Explanation: the ratio will never change no matter the air pressure!
Difference in density between the two liquids
Answer:
It is mentioned that the student is mixing chemicals A and B and observes the time taken for the color to change. However, in the experiment, it is noticed that the student has repeated the procedure five times and each time he or she is modifying the concentration of chemical B. Thus, it is clear that the concentration of chemical B is the independent variable in the experiment. An independent variable is illustrated as the variable, which is controlled or modified in the experiment.
