Small frogs eat small insects, such as crickets, grasshoppers, beetles and ants. They require more frequent feeding than their larger cousins, with most requiring feeding on a daily basis or at least several times per week.
The Radley Sanitarium is located in the fictional Darkette County, Pennsylvania. It plays into the series when Mona is in this facility, but we can guess it has something to do with the story Alison tells about the girl who was sent to a mental institution after killing her twin sister.
Radon is a radioactive gas that causes cancer. Radon is found in rock, soil, water, some building materials, and natural gas. You can't see, taste, or smell it. Any home, school, office, or other building can have high levels of radon. Radon is found in new and old buildings.