Canada is a federation composed of ten provinces and three territories. In turn, these may be grouped into four main regions: Western Canada, Central Canada, Atlantic Canada, and Northern Canada (''Eastern Canada'' refers to Central Canada and Atlantic Canada together). Provinces have more autonomy than territories, having responsibility for social programs such as health care, education, and welfare. Together, the provinces collect more revenue than the federal government, an almost unique structure among federations in the world. Using its spending powers, the federal government can initiate national policies in provincial areas, such as the ''Canada Health Act''; the provinces can opt out of these, but rarely do so in practice. Equalization payments are made by the federal government to ensure reasonably uniform standards of services and taxation are kept between the richer and poorer provinces.