This would prolly be smoking but i'm not exactly sure
Nitrogen is one of the elements found in the body
Answer:
the answers d. mate hope this helps
Answer:
B. Case-Control
Explanation:
A case-control is a study that compares a group with an outcome of interest (cases) with a group who do not have the outcome (controls). This study aims to looks back retrospectively to compare how frequently the exposure to a risk factor is present in each group and with that to determine the relationship between that risk factor and the outcome.
So in this case, the cases are children with pervasive development disorder and the control is those without the disorders.
These studies are normally observational because no intervention is attempted.
