What is an Organiser? Explain the role of Organiser in axis formation in amphibians. (UPSC 2017, 20 Marks, )

'आयोजक क्या है? उभयचरों में अक्ष निर्माण में आयोजक की भूमिका समझाएं।' (What is an Organiser? Explain the role of Organiser in axis formation in amphibians.)