Sentence:  This is brought out in the common religious ethos that prevails even in the denominationally diverse audiences at many secular semi-public and public occasions in the United States ; and it is evidenced in the prayers offered , in the frequent religious allusions , and in the confirmation of points on religious <WSD>grounds</WSD> . 
Meaning of the word marked with <WSD> tags:  your basis for belief or disbelief; knowledge on which to base belief