When connected to the internet, you will have the options to choose either Composite or Lowest Tilt radar.
Image 1. Internet radar options are Composite and Lowest Tilt.
When connected to an ADS-B the radar imagery available on the Maps page is only Composite. The Lowest Tilt selection will be grayed out and unusable.
Image 2. ADS-B only shows Composite radar.
To learn more about radar reflectivity, the NWS JetStream Online School for Weather: Introduction to Doppler Radar article is beneficial.
SiriusXM with the "Pilot for ForeFlight" subscription will show Radar (Lowest Tilt).