Group 1 - The importance of diversification in investment is emphasized, suggesting that a well-rounded portfolio should include a variety of stocks to mitigate risk [1] - Exchange-traded funds (ETFs) are highlighted as an effective way to achieve diversification, allowing investors to invest in multiple companies with a single investment [2] Group 2 - The Vanguard S&P 500 ETF (NYSEMKT: VOO) is recommended as a top investment due to its diversification, low expense ratio of 0.03%, and historical long-term returns of around 10% annually [4][6] - The S&P 500 includes companies from various sectors, making it a reflection of the U.S. economy's growth, despite its recent concentration in large tech stocks [5] - The Vanguard Russell 2000 ETF (NASDAQ: VTWO) focuses on small-cap stocks, which can offer higher growth opportunities but also come with increased risk due to their susceptibility to economic conditions [7][8]