根据短文内容，请将单词填写在题号对应的横线上。

    As is known to all, we live in a world of germs（细菌）. It is impossible to avoid exposure. Genetic makeups may give some people ____ advantage over others. However, it does not stop people from becoming sick.

    All of us have been a victim of an ____ (ill) at some point in our lives. Moreover, it is likely that we ____ (get) sick again in the future. Our best chances of avoiding sickness ____ (be) by exercising and employing good ____ (habit).

    While good hygiene and exercise serve as obvious advice to most people, eating ____ (healthy) is not always obvious. If you cannot define “healthy”, then your immune system will be happy ____ (tell) you. The immune system is the foundation of our health. It works for us every day to keep us well. Ask ____ (you): “Are you making its job easier ____ harder?”

    Like any system, the immune system is not different. It has a tolerance too. If you eat unhealthily, your immune system will make you aware of it.

    Take a step in the right direction ____ including some healthy food in your diet.