The human body is made up of four types of tissues. Which of the following structures make up tissues?
A. organs
B. cells
C. systems
D. organelles

Compare the depth of field when focusing with low power and high power. which power has the greater depth of field?

Which of the following was not a major animal on land during the carboniferous period? amphibians insects both a and b none of the above

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.