In thrips, the rasping and sucking mouthparts are asymmetrical due to the absence of:

✅ Explanation:The unique asymmetry of thrips' mouthparts, characterized by a rasping and sucking function, stems from the lack of the right mandible.

📌📌 Other options Explanation:
-Right Maxillae: While the maxillae play a role in food processing and manipulation.
-Left Mandible: The presence of the left mandible is crucial for the rasping function and wouldn't explain the asymmetry.