Calling the dependencies task allows you to see the dependencies of the root project:
gradle dependencies
The results are dependency graphs (taking into account transitive dependencies), broken down by configuration. To restrict the displayed configurations, you can pass the --configuration option followed by one chosen configuration to analyse:
gradle dependencies --configuration compile
To display dependencies of a subproject, use <subproject>:dependencies task. For example to list dependencies of a subproject named api:
gradle api:dependencies