Indicate the color of blood in each of the following cases: 1. Blood entering the lungs (alveoli):
2. Blood leaving the lungs (alveoli):
3. Blood entering the organs (cells):
4. Blood leaving the organs (cells):

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.

When a human or animal consumes food, the carbon in that food is most likely to be converted into which of the following elements? a. carbon remains carbon b. nitrogen c. oxygen d. hydrogen

Will give ! ! widentify the advantages and disadvantages of renewable and nonrenewable energy resources.