A.I. Explanation:

Option 1: "Lack of proper irrigation techniques"

Explanation: The text does not mention anything about improper irrigation techniques being associated with raising crops. Instead, it discusses overirrigation as a contributor to desertification, which implies that irrigation is being used, albeit excessively.

Option 2: "Failure to plant crops suited to the particular area"

Explanation: The text does not address the suitability of crops for specific areas. It focuses on the removal of natural vegetation and the consequences of crop failures, rather than the failure to plant appropriate crops.

Option 3: "Removal of the original vegetation"

Explanation: The text explicitly states that raising most crops requires the removal of natural vegetation. This is a direct connection to the process of raising crops, as it highlights the environmental impact of agricultural practices.

Option 4: "Excessive use of dried animal waste"

Explanation: The text does not mention the use of dried animal waste in relation to raising crops. Instead, it focuses on the activities that contribute to desertification, which do not include this option.