Polis (ˈpɒlᵻs, USˈpoʊlᵻs; πόλις, pólis), plural poleis (ˈpɒleɪz, πόλεις, póleːs), means 'city' in Greek. In Ancient Greece, it originally referred to an administrative and religious city center as distinct from the rest of the city. Later, it also came to mean the body of citizens under a city's jurisdiction. In modern historiography, the term is normally used to refer to the ancient Greek city-states, such as Classical Athens and its contemporaries, and thus is often translated as 'city-state'.
Agriculture began independently in different parts of the globe, and included a diverse range of taxa. At least eleven separate regions of the Old and New World were involved as independent centers of origin. The development of agriculture about 12,000 years ago changed the way humans lived. They switched from nomadic hunter-gatherer lifestyles to permanent settlements and farming. Wild grains were collected and eaten from at least 105,000 years ago. However, domestication did not occur until much later.
The Arab Agricultural Revolution was the transformation in agriculture in the Old World during the Islamic Golden Age (8th to 13th centuries). The agronomic literature of the time, with major books by Ibn Bassal and Abū l-Khayr al-Ishbīlī, demonstrates the extensive diffusion of useful plants to Medieval Spain (al-Andalus), and the growth in Islamic scientific knowledge of agriculture and horticulture. Medieval Arab historians and geographers described al-Andalus as a fertile and prosperous region with abundant water, full of fruit from trees such as the olive and pomegranate.
A mixed economy is variously defined as an economic system blending elements of a market economy with elements of a planned economy, markets with state interventionism, or private enterprise with public enterprise. Common to all mixed economies is a combination of free-market principles and principles of socialism. While there is no single definition of a mixed economy, one definition is about a mixture of markets with state interventionism, referring specifically to a capitalist market economy with strong regulatory oversight and extensive interventions into markets.