Describe how oxygen gas (O2) is produced during photosynthesis. Include the specific structures in the plant where the reaction occurs.

Which of the following diseases may be transmitted through an accidental needle stick? a. syphilis b. tuberculosis c. cellulitis d. hepatitis b

15 ! come and answer! a(n) disease is caused by a pathogen and can spread among organisms. a infectious b noninfectious c toxic d contaminated

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.