Private schools, in place of public schools, require the consent of the State and must conform to Land law. The consent of the State must be given if such private schools are not inferior to the public schools in respect of their educational aims and arrangements, and in respect of the professional standard of their teaching staffs, and if no distinctions are made between scholar and scholar on account of the financial position of their parents. Consent shall be refused if the financial and legal position of the teaching staff be not sufficiently secured. Private elementary schools may only be set up if a minority of parents or guardians, claiming consideration under Clause 2 of Article 146, have no public elementary school for their faith or views, or if the educational administrative authorities recognise that special educational interests are involved. Private preparatory schools are abolished. The legal status of private schools which do not take the place of public schools is unchanged. ARTICLE 148. All schools shall aim at inculcating moral character, a civic conscience, personal and professional efficiency in the spirit of the German national character and of international conciliation. The teacher in public schools shall avoid offence to those of contrary opinion. Education in citizenship and technical instruction are part of the curricula. Every scholar shall, on leaving school, receive a copy of the constitution. Realm, Lands, and Local Authorities shall promote popular and university education. ARTICLE 149. Religious instruction is an ordinary part of the curriculum except in the non-religious (secular) schools. It shall be regulated by the legislation on education. Religious instruction shall be given in harmony with the principles of the religious association concerned, without prejudice to the control of the State. The giving of religious instruction and the instituting of Church ceremonies shall be dependent on consent of the teacher; the acceptance of religious instruction and participation in Church ceremonies and acts shall be dependent on consent of those persons responsible for a child's religious education. The theological faculties in the Universities shall be maintained. ARTICLE 150. Monuments of artistic, historic, natural, or picturesque interest shall be under the protection and care of the State. The Realm is responsible for preventing the export of German artistic treasures to foreign countries. SECTION V--THE ECONOMIC SYSTEM.[42] ARTICLE 151. The social economic system must conform to the principles of equity with the special object of guaranteeing an honourable livelihood to all. Within these limits economic freedom shall be secured to each individual. Legal compulsion is only admissible to maintain rights which have been threatened or to secure an overwhelming public interest. Freedom of trade and of manufacture shall be guaranteed by acts of the Realm. ARTICLE 152.