How is UTI Nifty Index fund beneficial in case of long term investment?

I am looking to invest in Nifty or Sensex as part of long term investment. Do you recommend an index fund or an index ETF?

How long-term gains and short-term gains are calculated in case of debt fund investments?

Due to bad news some good fundamental stocks falls very huge after that, can we add it in our portfolio, for long term investment?

Can I use systematic selling of equity funds to avoid paying a huge capital gains tax on long term gains? Is that feasible?

Is the benefit of indexation available to short term capital gains and also to long term capital gains?

How is the definition of long term and short term assets different in case of equity shares?

How will the classification of long term capital asset be done in case of unlisted shares?

Does the definition of 12 months apply in case of house property or 36 months for the long term asset classification?

Can you tell me how double indexation benefit works in case of debt funds?

What is the reason for the fall in profits of Maruti in the June quarter? Can I buy the stock at these levels for the long term?