A binomial model is arguably a heavily simplified framework for deriving the valuation of options. Explain three reasons why it still makes sense to study option valuation within such a framework ?

Give a verbal (!) explanation of the reasoning that leads to the derivation of the black-scholes option pricing formula ?

What is the so-called "delta" of an option ? What is the lower and the upper bound ( i.e. the minimum, maximum value) for the delta of a call option ? Suppose, the delta fo a call option is 0,7 ?
Is it true that the delta of a put option ( on the same underlying and all else equal ) is 0,7 ? Explain your answer !