This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Example input: Passage: The French and Indian War (17541763) was the North American theater of the worldwide Seven Years' War. The war was fought between the colonies of British America and New France, with both sides supported by military units from their parent countries of Great Britain and France, as well as Native American allies. At the start of the war, the French North American colonies had a population of roughly 60,000 European settlers, compared with 2 million in the British North American colonies. The outnumbered French particularly depended on the Indians. Long in conflict, the metropole nations declared war on each other in 1756, escalating the war from a regional affair into an intercontinental conflict. Question: When was the French and Indian War?
Example output: 1754-1763
Example explanation: It is a common convention to write (start year-end year) beside a historical event to understand when the event happened. We can observe a similar notation from the passage to conclude that the French and Indian War happened during 17541763. Therefore, the answer is 17541763.
Q: Passage: Biggeri and Mehrotra have studied the macroeconomic factors that encourage child labour. They focus their study on five Asian nations including India, Pakistan, Indonesia, Thailand and Philippines. They suggest that child labour is a serious problem in all five, but it is not a new problem. Macroeconomic causes encouraged widespread child labour across the world, over most of human history. They suggest that the causes for child labour include both the demand and the supply side. While poverty and unavailability of good schools explain the child labour supply side, they suggest that the growth of low-paying informal economy rather than higher paying formal economy is amongst the causes of the demand side. Other scholars too suggest that inflexible labour market, sise of informal economy, inability of industries to scale up and lack of modern manufacturing technologies are major macroeconomic factors affecting demand and acceptability of child labour. Question: Supply and what else causes child labour to still exist today?
A:
demand