Which of these statements about light microscopes and electron microscopes is not true?
a. you can use light microscopes to observe both living and nonliving cells; you can use electron microscopes to observe only nonliving cells.
b. light microscopes use visible light rays; electron microscopes use beams of electrons.
c. preserving and staining samples for use with light microscopes is necessary; preserving and staining samples for use with electron microscopes is optional.

Which of the following statements is correct in hour our immune system responds to a potential pathogen? a. the adapted immune system will call on the innate immune system to destroy the pathogen. b. b cells will start reading the antigen code immediately and call t cells to assist in destroying the pathogen. c. the skin will be the first line of defense, and then the many phagocytes in the bloodstream will attempt to consume the possible pathogen. d. the t-cells in the adapted immune systems are the first to recognize the pathogen vaccines are weakened forms of disease causing microorganisms, which are given to patients to prevent disease. after the vaccine is administered, the immune system responds by creating a(n) to recognize the a. antigen, antibody b. antibody, antigen c. antibody, antibiotic d. antibiotic, antibody