A.radial B.sheath-screw C.gravity D.quadrantal
A.shape of the anchor B.stowage of the anchor on board C.anchor's ability to dig in D.size of the vessel and its draft
A.control the pressure of the oxygen as it enters the body B.allow the wearer to manually give himself oxygen C.release excess heat which would otherwise cause the bottle to explode D.allow exhaled gases to pass outside the bottle