Air moves into the lungs because

A) the gas pressure in the lungs is less than outside pressure.
B) the volume of the lungs decreases with inspiration.
C) the thorax is muscular.
D) contraction of the diaphragm decreases the volume of the pleural cavity.
E) all of these.

The hershey and chase experiments involved the preparation of two different types of radioactively labeled phage. which of the following best explains why two preparations were required? a. the bacteriophage used in the experiments was a t2 phage. b. it was necessary that each of the two phage components, dna and protein, be identifiable upon recovery at the end of the experiment. c. each scientist had his own method for labeling phage, so each conducted the same experiment using a different isotope. d. establishing the identity of the genetic material required observation of two phage generations.