Early writings on the subject tended to judge states by the realist criterion, as expressed by the historian A. J. P. Taylor when he noted that "The test of a great power is the test of strength for war." Later writers have expanded this test, attempting to define power in terms of overall military, economic, and political capacity. Kenneth Waltz, the founder of the neorealist theory of international relations, uses a set of five criteria to determine great power: population and territory; resource endowment; economic capability; political stability and competence; and military strength. These expanded criteria can be divided into three heads: power capabilities, spatial aspects, and status.
Who wrote, "The test of a great power is the test of strength for war."?
A. J. P. Taylor

Many factors played a role in Britain's long-term economic growth, such as the industrial revolution in the late 1700s and the prominent presence of child labour during the industrial age. Children who worked at an early age were often not forced; but did so because they needed to help their family survive financially. Due to poor employment opportunities for many parents, sending their children to work on farms and in factories was a way to help feed and support the family. Child Labour first started to occur in England when household businesses were turned into local labour markets that mass-produced the once homemade goods. Because children often helped produce the goods out of their homes, working in a factory to make those same goods was a simple change for many of these youths. Although there are many counts of children under the age of ten working for factories, the majority of children workers were between the ages of ten and fourteen. This age range was an important time for many youths as they were first helping to provide for their families; while also transitioning to save for their own future families.
Why was this age range important?
they were first helping to provide for their families; while also transitioning to save for their own future families

After they each performed, both were deemed equal until Apollo decreed they play and sing at the same time. As Apollo played the lyre, this was easy to do. Marsyas could not do this, as he only knew how to use the flute and could not sing at the same time. Apollo was declared the winner because of this. Apollo flayed Marsyas alive in a cave near Celaenae in Phrygia for his hubris to challenge a god. He then nailed Marsyas' shaggy skin to a nearby pine-tree. Marsyas' blood turned into the river Marsyas.
What instrument did Apolo play?
lyre