Questions 21-25 are based on the following procedure.

                                     
Seafood-Filled Tofu

Ingredients:

• 4 pieces of white tofu
• frying oil 

For the dipping:

• 2 eggs, beaten
• 1/2 tsp of pepper
• salt                                  

For the filling:

• 150 g of peeled shrimps,chopped
• 150 g of fish fillet, chopped
• 150 g of squid, chopped
• 1 tbsp of tapioca
• 1 stalk of scallion, sliced
• 1 tsp of salty soy sauce
• 1 tsp of sesame oil
• 1/2 tsp of pepper powder
• salt

How to make it:

1. Cut the tofu into two. Take some part of the tofu to make a long hole. Set aside.
2. Mix all ingredients for the filling .
3. Fill the hole on the tofu with the filling.
4. Steam the filled tofu for about 45 minutes.
5. Cool it.
6. Heat the oil.
7. Dip the tofu into the dipping, deep fry until golden brown.
8. Serve it with chili sauce.

The main ingredient of the filling is ....