Environmentalists worry that the heavy use of plastic packaging will pollute the environment and try to get manufacturers to find ways to recycle plastic materials. However, despite their efforts, the recycling rate of plastic products is only 6.5%. The recycling rate of glass containers is 33%. If the following ______ items are true, they will not help explain the relatively low recovery rate of plastic products. ['Many factories can recycle glass, but only a few factories can use recycled plastic for production.', 'Many plastic products are incompatible and cannot be recycled, and most glass products are compatible.', 'New plastics require more oil, and new glass can use renewable resources.', 'The quality of products made from recycled plastic is poor, while recycled glass does not have such problems.']