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.
An economy is a system of institutions and organizations that either help facilitate or are directly involved in the production and distribution of goods and services. Economic resources are the inputs we use to produce and distribute goods and services. The precise proportion of each factor of production will vary from product to product and from service to service, and the goal is to make the most effective use of the resources that maximizes output at the least possible cost.