J. j thomsons cathode-ray tube experiment showed which of the following
a. electrons are in a cloud surrounding positively charged particles
b. atoms consist of at least some negatively charged particles
c. atoms are small individual spheres
d. matter can be neither created or destroyed

In trying to determine whether dna or protein is the genetic material, hershey and chase made use of which of the following facts? a) dna contains sulfur, whereas protein does not. b) dna contains phosphorus, whereas protein does not. c) dna contains nitrogen, whereas protein does not. d) dna contains purines, whereas protein includes pyrimidines.