Here are the correct answers for each gap in the text with explanations:
* **A:** The correct answer is **2) has been**. The sentence needs a singular verb because 'bread' is singular and the time frame is continuous. 'Was' is not correct because it implies the bread is no longer a staple food.
* **B:** The correct answer is **1) began**. The sentence describes a past action, the beginning of bread making. Therefore the simple past tense is used.
* **C:** The correct answer is **2) this**. We need singular word because 'flour' is uncountable singular noun. 'These' is plural.
* **D:** The correct answer is **3) which**. The word 'flatbreads' refers to a object, and we need a connecting word for clause. 'Who' is for people, 'whose' refers to possession.
* **E:** The correct answer is **3) can**. The context describes the possibility to find bread, so 'can' is used.
**Summary of Answers**:
* A: 2
* B: 1
* C: 2
* D: 3
* E: 3