Countless research studies have examined the correlation between the number of hours an adolescent works and problems they may experience. It is clear that when a teenager works beyond hours a week, problems arise, and beyond hours a week the problems become considerably worse.

10; 20

Explanation:Research is defined as the creation of new knowledge and/or the use of existing knowledge in a new and creative way so as to generate new concepts, methodologies and understandings. This could include synthesis and analysis of previous research to the extent that it leads to new and creative outcomes.

For example, clinical trials are research studies that involve people. These studies may be related to new ways to screen, prevent, diagnose, and treat disease.

10;20.

Explanation:

One of the problems that do affect the development of adolescents is the issue of working for too much hours. Apart from the time at which adolescents work, another thing related to it is the kind of work adolescents are doing(that is to say whether is a hard labour or not, part -time or full time work). The body is never a stone and adolescence stage of humans is a very important and crucial stage. Therefore, all long time working will later affect adolescents.

According to research, When adolescents work for over 20 hours they develop more problems.

answer; longitudinal;