You read in a news article on the web about a study that found that older adults who exercise regularly are less likely to develop dementia (i.e., a decline in cognitive abilities) as they age....

You read in a news article on the web about a study that found that older adults who exercise regularly are less likely to develop dementia (i.e., a decline in cognitive abilities) as they age. Describe three different types of causal relationships that could be present in this study’s results. (Hint: Use Figure 15.1 as a model for the three types of causal relationships possible.)