Answer:
They are stimulated by an antigen.
Explanation:
Natural killer cells are cytotoxic cells that help our body in innate immune response. These are an critical and important component of the innate immune system of our body. These natural killer cells provide a rapid response towards the virus infected cells. These cells have capability to detect MHC that are present on the infected cells. Natural killer cells do not require activation for killing those cells which are missing MHC I. Due to this feature, they are named as the Natural killer cells. These cells can directly induce the death of tumor cells and play an important role in immunosurveillance.
A forest typically has a water source, with other natural occurring things where as a corn field doesn't have a lot of protective things. Like a forest has a bigger food chain where a cornfield mostly has mice and snakes and that's it. A forest just has more things to help it thrive
