I've had the same question, the answer is longitude.
Answer:
Wikipedia defines formal sector as activities which are taxed and monitored by the government and the activities involved are included in the Gross Domestic Product(GDP).
Explanation:
In contrast to formal economy is the informal sector which is neither taxed nor included in the GDP and Gross national product (GNP) of a country.
Explanation:
Ecosystems exist at a range of scales and involve the interaction between biotic and abiotic components. An example of a small scale UK ecosystem to illustrate the concept of interrelationships within a natural system, an understanding of producers, consumers, decomposers, food chain, food web and nutrient cycling.
Those geographic helped to protect the Roman Empire.