问题
问答题
In the emerging area of biofuels, the problem is both restrictive tariffs and heavy subsidies in rich countries, which drive up food prices and limit export opportunities for efficient developing country producers.
答案
参考答案：
解析：在新兴生物燃料领域，诸多发达国家的限制性关税和高额补贴都给出口造成困难，这些困难导致粮食价格上涨，限制发展中国家高效生产商的出口机会。