Excessive sun exposure is a common cause of brown spots on the scalp due to conditions such as melasma and actinic keratosis, per the Mayo Clinic and the American Academy of Dermatology. While these conditions differ slightly from each other, they both are frequently caused by excessive ultraviolet radiation. Continue Reading.
Mexico is a part of North America. Maybe you are thinking of Northern America, which is a tricky area as sometimes Mexico is included and sometimes it is not. Northern America â¦ is the northern portion of North America, in which Canada and the United States are usually the two sole members.
Mexico, the southernmost country of North American, borders the northern countries of Central America, Guatemala, and Belize. However, the main flows of Central American nationals headed to the United States usually cross Mexico's border with Guatemala.istorical background. After Mexico and Central America gained independence from Spain, in 1821, the Central American states came briefly under Mexican rule before separating in 1823 and creating a unified nation called the United Provinces of Central America.