Answer with Explanation:
The investment in securities must include purchases of stock of more than 15 industry firms because diversified investment gives an average rate of return on investments. Hence it would be better to lower the risk of investment by simply investing in more than 15 firms and each of them must be from different industry sector. Nowadays due to coronavirus, it would be better to investing in fintech, IT and Hi-Tech industries will pay much more than low tech industries. Tesla is one of these tech companies whose share price have surged by 390% in past 12 months. It doesn't mean that other industry products don't pay enough. Setting objective includes how much yearly investment must be added to you security portfolio so that the net worth of the portfolio keeps growing. The reinvestment of dividends received, insurance of downside risk, investment on the basis of value at risk, etc. are all the set objectives that are considered while investing and managing security portfolio. If you are not confident with setting objectives then investing via investment institutions would be a another best option which had employed hundreds of CFA's who are working to increase the wealth of their potential clients and it is more likely that you take home a better return on investment as compared to a person who has little knowledge of security investments.