The primary hormone produced by the male testes is testosterone, a steroid hormone important in the development of the male reproductive system, the maturation of sperm cells, and the development of male secondary sex characteristics such as a deepened voice, body hair, and increased muscle mass.
Foreign investments in the US average $2.4 trillion, while American investments in other countries total $3.3 trillion. Consumer spending comprised 71% of the US economy in 2013, and the United States has the largest consumer market in the world. As a result, the US possesses not only the largest economy, but also one of the most stable in the world. Economic History. The United States has had the world's largest national economyânot including the benefit of colonial empiresâsince the 1890s.
The United States is the world's largest national economy, representing 22% of nominal global GDP and 17% of global GDP (PPP) .The United States' GDP was estimated to be $17.914 trillion as of Q2 2015. The U.S. dollar is the currency most used in international transactions and is the world's foremost reserve currency.Several countries use it as their official currency, and in many others it is the de facto currency.he American colonies went from marginally successful colonial economies to a small, independent farming economy, which in 1776 became the United States of America. In 180 years, the US grew to a huge, integrated, industrialized economy that made up around one fifth of the world economy.