Helper T cells become activated by interacting with antigen presenting cells. and the second blank space is either cytotoxic t cells or B cells
Answer:The tree was once alive so its considered a biotic factor
Explanation:
One example of how natural selection can change the distribution of a trait is the peppered moths during the industrial revolution. The moths were originally mainly white with a few black spots, however, when all the factories were built, the trees the peppered moths lived on turned a black color, causing ones who were mostly white to be picked off by predators, but the ones that were black with a few white spots survived and blended in better, leaving them to breed and produce more black-colored moths that would survive easily. This shows the changing of a trait because ones that used to be mostly white were killed, showing a shift in the trait pattern in favor to the black moths that now lived instead of the white moths. (Sorry its long)
