I'm new to investing and I recently opened a Roth IRA. I know that index funds are a good choice for investing because they have low expense ratios and are diversified. Also, because track a whole industry, they cannot crash to zero value (unless the whole industry crashes to zero).
When I opened my IRA I was faced with a long list of index funds to choose from. I read this question on what to consider when choosing an index fund, but it isn't clear to me if I should pick one index fund for all* my investments or if I should be splitting my money between two, or three, or ten index funds.
How many index funds should I invest in? Since an index fund is already diversified, is it still beneficial to invest in more than one index fund?
*I will of course hold some money in fixed income like bonds