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.
EE savings bonds reach their initial maturity after 20 years from the purchase date and are guaranteed to at least double in value at that time. They continue to earn interest for another ten years after maturity, so you can hold them for 30 years, if you like.