Making the world better, one answer at a time. a superbug is a micro-organism that is resistant to most anti-biotics. the superbugs in recent history are imune to all anti-biotics,except one.
Both electronic and paper versions of Series I savings bonds are purchased at face value and earn interest until they are redeemed or reach maturity. You must hold Series I bonds for at least 12 months before redeeming them. Series I savings bonds will continue to earn interest for up to 30 years. They will cease paying interest once they have matured.
These EE bonds earn the same rate of interest (a fixed rate) for up to 30 years. When you buy the bond, you know what rate of interest it will earn. Treasury announces the rate each May 1 and November 1 for new EE bonds. See: Comparing I Bonds to EE Bonds.