What is a volatility smile? What is a volatility smirk? What volatility pattern is observed for

equity? What volatility pattern is observed for crude oil futures?

What is the volatility pattern $($volatility vs$.$ K$/$F$)$ if

True distribution has a heavy left tail than the corresponding normal distribution?

True distribution has a heavy right tail than the corresponding normal distribution?

At$-$the$-$money implied volatilities are lower than in$-$the$-$money or out$-$of$-$the$-$money

options?