Part of the reason for the stock market crash was? :
a the high rate of deflation in the 1920s.
b the tax policies of the 1920s, which especially hurt the wealthy who might otherwise have brought more stocks.
c the buying of great amounts of stock "on margin."
d the low tariff, which allowed imports to corner several important american markets.

depends on the age of the teen, many believe by the age of 16 a person should know the strong difference between right and wrong along with the difference between risky and immediate death. swimming with sharks might be dangerous but swimming with sharks while bloody meat is attached to you is just insane. even more if you have no idea what you're doing. however, no matter the age, as long as the person is skilled enough and has the mental and physical capacity to control their actions doing whatever sport they put their mind to is all that matters.