You have been put in charge of designing an ad campaign for your area to get more people to use public transportation. One part of the campaign is a poster that draws people's attention and informs them of their choices. What are three reasons you could add to your poster to encourage people to use public transportation?

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.