Questions

Bitcoin is the world's first cryptocurrency,    a    form    of electronic   cash.It   is   the    first decentralized digital  currency:  the system   was   designed   to   work without   acentral   bankor   single administrator.Bitcoins    are    sent from  user  to  user  on  the peer-to-peer bitcoin network directly, without the need for intermediaries.  These  transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a block chain. Bitcoin was invented by an unknown person or group of people   using   the   name Satoshi Nakamoto. Bitcoins are not recognised  as  a  legal  tender  by Reserve Bank of India. 

‘Regret for’ needs to be replaced with ‘regret’ to make the sentence grammatically correct. This is because ‘regret’ is not followed by a preposition. Thus, the correct formation would be, ‘I regret using objectionable words against a man so mighty’.

Numismatist: someone who studies or collects coins, paper money, or medals.

Philatelist: a person who collects stamps.

Ornithologist: a person who studies on birds.

Statistician: an expert in the preparation and analysis of statistics.