लाइकेन का व्यापक रूप से किस प्रकार के प्रदूषण के प्राकृतिक जैव-संकेतक (बायोइंडिकेटर) के रूप में उपयोग किया जाता है?

In the context of chemical pollution, what specific fatal reproductive issue is caused in raptor bird populations due to the bioaccumulation of pesticides like DDT within the food chain?

In the districts of Murshidabad and Nadia in West Bengal, which of the following naturally occurring (geogenic) pollutants is found in high levels in groundwater due to sedimentary deposits?