Answer:
1 st question ) Lack of food and oxygen and the presence of wastes limit their growth.
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.
I think they are called that because of the food we eat.
Limestone becomes C) Marble with heat and pressure
