A convecting mantle is an essential feature of plate tectonics and contributes to the formation of both igneous and metamorphic rocks. Where does the thermal energy that drives these convection currents come from?
A) The convection of the mantle is driven by the heat gradient within the mantle layer itself.
B) The convection of the mantle is a product of the transfer of heat from the core to the lower mantle.
C) The convection of the mantle is the result of the radioactive decay of nickel occurring within the core.
D) The heat is the frictional heat from the rotating fluids within the core of the Earth which rises up into the mantle.


Which of the following statements is correct in hour our immune system responds to a potential pathogen? a. the adapted immune system will call on the innate immune system to destroy the pathogen. b. b cells will start reading the antigen code immediately and call t cells to assist in destroying the pathogen. c. the skin will be the first line of defense, and then the many phagocytes in the bloodstream will attempt to consume the possible pathogen. d. the t-cells in the adapted immune systems are the first to recognize the pathogen vaccines are weakened forms of disease causing microorganisms, which are given to patients to prevent disease. after the vaccine is administered, the immune system responds by creating a(n) to recognize the a. antigen, antibody b. antibody, antigen c. antibody, antibiotic d. antibiotic, antibody