There are no web services for this because no-one has ever needed them enough to implement them.
Opaque is the answer to a different question.
Quiz
Web Services To Access Moodle Questions
ການສົນທະນາຖືກລັອກ ດັ່ງນັ້ນ ທ່ານບໍ່ມາສາດຕອບກັບມັນ.