Which of the following statements about cell differentiation is true? A. Cell differentiation occurs only in adult organisms
B. Cell differentiation cannot be affected by the environment
C. Cells differentiate because the dna in each cell of an organism is different
D. Cells differentiate because different areas of the dna are activated in each cell type.

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.

Which of the following is a period in the paleozoic era? devonian cambrian permian all of the above

Matched chromosomes carrying information about the same characteristics in the organism are called