单选题 Scientists assume that unrestrained population growth and dwindling resources may force humans to look to the sea for food.
【正确答案】 B
【答案解析】[解析] unrestrain是restrain的反义词，意思是“不受控制的”，与unexpect可替换。unavoidable不可避免的；unchecked不受检查的；unfortunate不走运的。故选B项。