The graph shows the radioactive decay of carbon-14.

a fossil originally had 254 grams of carbon-14 but currently has 127 grams of carbon-14. the fossil is most likely

group of answer choices

5,730 years old

11,460 years old

17,190 years old

22,920 years old

Twind is considered to be an abiotic factor because it.?

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.

Regarding most of the narrator’s story, which word best describes the tone?