The definition of symbiosis has varied among scientists. Some believe symbiosis should only refer to persistent mutualisms, while others believe it should apply to any type of persistent biological interaction (i.e. mutualistic, commensalistic, or parasitic).
The Golden Pledge, which is a System Plus Warranty with a 20 year leak guarantee, can pay for itself within the first ten years, sometimes many times over. The System Plus transforms the normal warranty by removing the small print.
Pledge (law) For other uses, see Pledge (disambiguation). A pledge is a bailment that conveys possessory title to property owned by a debtor (the pledgor) to a creditor (the pledgee) to secure repayment for some debt or obligation and to the mutual benefit of both parties. The term is also used to denote the property which constitutes the security.