Responding to a query for a grant to attend conference
Should I respond them back simply in the form of email?


Yes, it is far easier to process.


  Should my answer be very detailed or just to the point?


Either, but if it is detailed, then structure is key: Reply in a manner that the reader can stop reading as soon as they are satisfied. This likely requires you to open with a single paragraph summary (possibly concluding with "Further details are provided below, should you be interested" or similar).


  Any other do's and dont's !


If XXX will bring connectivity to an isolated individual, then the application of your research is seemingly narrower than the organisers would like. Otherwise, make sure to explain how XXX brings connectivity to more than an isolated individual.