Writing and Reading

      [1] The results of genetic tests are not always “yes or no” for the presence or the risk for developing disease, which make interpretations and explanations difficult. [2] In most cases, diseases occur as a result of interaction among multiple genes and the environment—for example, a person’s lifestyle, the foods they eat, and the substances to which they’re exposed, like sunlight, chemicals, and tobacco. [3] The interactions of these factors in contributing to health and disease can be very complex. [4] A positive result means that the testing laboratory found unusual characteristics or changes in the genes it tested. [5] Depending on the purpose of the test, that result may confirm a diagnosis, identify an increased risk of developing a disease, or indicate that a person is a carrier for a particular disease. [6] It does not necessarily mean that a disease will develop, or if it does, that the disease will be progressive or severe.

To make this paragraph most logical, sentence 3 should be placed