In the united states, most individuals begin school around age 5, whereas in australia they start at 3. this is an illustration of how development is

It is the contextual development. Contextual learning depends on a constructivist hypothesis of educating and learning. Learning happens when instructors can show data in a way that understudies can build significance in light of their own encounters. This type of learning will enhance your problem-solving skills. 

The changes to agriculture in the united states since 1900 is that increased mechanization has increased food production, thereby increasing the need for labor. there has been an increased need for higher speeds of food production due the fact that the population in the united states continues to rise.