The right answer is "Different age groups are tested at the same time". This type of research is known as A Cross-Sequential Design. These investigations have a cross-sectional and longitudinal, involves analyzing a group of people of different ages (For example 10, 20, 30 and 40 years) over time (For example, for 40 years), this in order to study human development in a particularly long period of life.
I hope my answer can help you.
The system of feudalism needed a lot of workers, who were tied to the land, and had to deliver a part of their harvest to their lords. The farmers generally had a poor life and struggled to make enough both for themselves and for the lords, but the lords benefited from this, as they had many farmers paying them a part of their harvest
Before the plague, the land was scarce, but people plenty, which meant that the farmers could not set conditions on their work. After the plague the number of farmers decreased, and there was a lot of work needed, so the farmers could search for a different place to work, if the feudal lords were demanding too much,.
Airways, roadways, railways, and waterways.
Spend more time with family.Happiness is the best medicine for events like that
