Here are the correct answers for the options provided:

1. **D. is** - "There are many reasons why it is important to have a hobby."
2. **A. and** - "It will give you a pleasure and help you relax."
3. **C. grow** - "They grow a lot of trees and vegetables, so they can sell them for some money."
4. **C. collecting** - "If you like collecting stamps, you can join a stamp club..."
5. **B. for** - "you can give your products to your friends for gifts."

So the filled passage would read:

"There are many reasons why it **is** important to have a hobby. It will give you a pleasure **and** help you relax. Many old people enjoy gardening. They **grow** a lot of trees and vegetables, so they can sell them for some money. In addition, a hobby can help you connect with other people. If you like **collecting** stamps, you can join a stamp club to share your albums with other collectors. If your hobby is carving eggshells, you can give your products to your friends **for** gifts."