Answer:
<em>In biochemistry and pharmacology, receptors are chemical structures, composed of protein, that receive and transduce signals that may be integrated into biological systems</em>
Trees can be made again . Water is a natural resource fuel is too . Wind
Answer:
secrete a cytokine that triggers apoptosis
Explanation:
Cytotoxic T cells secrete granzymes and perforins when targeting cells. Additionally they secrete cytokines such as IFN-, TNF-α and TNF-β that act to activate macrophages and help kill infected cells.
