Natural rubber is. It literally grows on trees. Or, more literally, it drips from trees. http://en.wikipedia.org/wiki/Natural_rubber Synthetic rubber is a petrochemical product, so it isn't. read more
Natural rubber definitely, but synthetic rubber is not renewable. On reason, it could be regenerated without an artificial imput. Natura rubber is a sap obtain via stem grafting from the trucks of the rubber tree ( fitcus elastica) and if harvested sustainably would replenish its quantity. read more
A renewable resource is a natural resource which replenishes to overcome resource depletion caused by usage and consumption, either through biological reproduction or other naturally recurring processes in a finite amount of time in a human time scale. read more