D. fossils will help you discover how old the rock is, fossils would not be included in the question if the answer does not relate to them
No. Ionic bonds form when atoms with opposite charges bond with one another. Atoms develop charges by gaining or losing electrons. For a given element, the atoms will (usually) have a tendency to gain OR lose a particular number of electrons, so they can only form ions of a particular charge that is either positive or negative.
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.
Answer:Latitude and ocean currents