Where UTF-8 is replaced with the character encoding you want to use and .html is a file extension that this will be applied to. This character encoding will then be set for any file directly in or in the subdirectories of directory you place this file in.
A Barr body is the inactivated X chromosome that is usually found in the nuclei of female somatic cells. It can also occur in males when there is an abnormality and the male is XXY instead of the normal XY, a condition known as Klinefelter's syndrome.
Natural killer cells are a part of the lymphoid linage of white blood cells. The body responds to viruses by secreting cytokines that disrupt viral replication and make the cell more susceptible to attack by NK cells. The primary cytokine released by NK cells is type II interferon, which activates macrophages.