What would be the best buy and hold stock for a 20 year old?

Definitely a growth stock in a rising industry - I'm thinking the Electric Vehicle industry, a stock like TESLA (NASDAQ: TSLA). Though currently TESLA is having a bit of trouble with imports into China, the CFO leaving recently and Elon Musk getting slapped with a charge by the SEC for blurting out information on twitter, TESLA's continued popularity, standing and leader of the autopilot + EV industry is undeniable, currently standing at 10% of all EV demand in the world. Elon and his company has led the way in a sustainable transportation revolution, and this may truly be the future of all our transportation once our natural fuels start running low, and the cost gets higher and highe to use them.

EVs will definitely be the way to go (unless, of course, we somehow managed to create a self contained safe nuclear powered car that runs almost infinitely on clean energy), so TESLA will have a huge say and growth in the near future. I think if you want to hold onto a potential huge stock, TESLA is a good bet.

Hello! Personally, I invest in Amazon (NASDAQ:AMZN). While Amazon may not be an undervalued stock, it has a high P/E ratio and has a long runway for growth. Amazon is also founder-run company which has resulted in a strong emphasis for doing things with an eye to the long-term. The founder Jeff Bezos is the largest single owner of AMZN stocks, so his interests are clearly aligned with the shareholders. Amazon is consistently willing and desiring to become a disruptive force in a variety of industries. For instance, entering the grocery industry with the Whole Foods acquisition and healthcare industry by teaming up with Berkshire Hathaway and JPMorgan Chase & Co. Bezos's long term approach gives Amazone a sustainable competitive advantage proving Amazon's large growth prospects.