给定一篇文章，请对其中出现的英文名词区分它们的单复数形式，将它们分类成单数或是复数形式。



The causes of poverty are manifold, and there is often no simple solution. For example, some people are poor because they lack access to education; others are poor because they live in regions where there are few job opportunities. Still others are poor because of health problems or because they have been victims of natural disasters. Whatever the cause, it is important for society to address poverty and to work towards creating a fairer and more just world.
单数：cause, solution, person, access, education, region, job opportunity, health problem, victim, natural disaster, society, world

复数: people