Coupleof questions about Bull and Bear markets

When a Bull market turns a into a Bear market is there a defining moment, or is it more of a defining trend over 'x' period of time? For example say a dip starts to appear in the market, what is it about that dip that specifically makes it become a Bear market?

A handful of articles I've read make the Bear market sound like a bad situation yet people obviously still invest in a Bear market. I'm a tad confused , if it was bad why would people be investing ?

Sorry I know these are at the 101 level for some of you but I' still in the acquiring knowledge process...

Fundamental investors will often take a contrarian approach and acquire shares in the soft cycle. The downside is this can mean they buy while the share price is still falling but the upside is that there are plenty of shares on offer and the better quality companies still pay dividends but at higher yields than a bull market delivers.

There are all sorts of ways to play recessions and bear markets. I prefer growth companies in a recession as investors tend to pay more for growth in a low growth environment - the trick is picking who can grow in a recession...