Sure, here are the correct word forms for the words in brackets:

1. I'm **allergic** to seafood. (allergy)
2. If you don't sleep well the night before, you can't **concentrate** on your studies or work. (concentration)
3. Whenever I feel **depressed**, I usually go to the countryside to enjoy the fresh air. (depress)
4. Lung cancer is the leading cause of cancer **deaths** worldwide. (die)
5. There are 3 ways to lead a **healthy** lifestyle: eating food, drinking fluids, and exercising. (health)
6. Let's do more **physical** activities like sport and housework to keep us fit and active. (physic)
7. Do you know the **importance** of sleep? (important)
8. Healthy food, love and **laughter** bring us a healthy life. (laugh)
9. Smoking is **harmful** to your health. (harm)
10. You look so tired these days. I think you should laugh more and stay **relaxed**, Anna. (relax)