Other people believe that getting money or other rewards makes kids do chores happily and it also teaches them real-world lessons about what we need to do to make money.
The symbolism may come from the fact that the olive tree takes a long time to produce fruit, so olives could only be cultivated successfully in long periods of peace.
Known as the "low countries" because much of the land is now below sea level, many of the country's largest cities are kept dry only by huge walls holding back the sea.
What's more, demand for animal products in developing countries is growing so fast that meeting it will require an extra 300 million tons of grain a year by 2050.