Aresearcher isolates the blood of an individual who is sick. the blood is filtered through a porous material that will prevent all cells from passing through. the filtered serum of the blood is then injected into a healthy patient. this patient shows signs of the illness within days of the inoculation. what is the most likely causal agent of the disease based on this information? a) a virus b) a fungal pathogen c) a bacterial pathogen d) a protozoan parasite

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.

Aboy jumps into a cold swimming pool and his body tempature goes down hus muscles ,blood vessels

Many organizations release indexes used to measure the development of the world's countries. as we learned in this lesson, these indexes measure many factors, from life expectancy to happiness. in your opinion, what are the three most important factors we can use to determine how developed a country might be? explain your answers in a few sentences.