Dad taught me to diversity and not put all eggs into 1 baske...

Dad taught me to diversity and not put all eggs into 1 basket. The same logic applies: spead across countries and sectors when buying stocks to set a safety net. I'm applying to my 8 year old son asking questions like: does airline value drops during covid, what happens when the borders opens up, how about the current sectors that are on uptrend? He's enjoying the debate through deep thinking!