What was a change proposed by the Single European Act? Multiple Choice establish frontier controls among European Community countries reduce costs directly by not allowing lower-cost suppliers into national economies increase the resources required for complying with trade bureaucracy apply the principle of "mutual recognition" to product standards place barriers to competition in the retail banking and insurance businesses

Apply the principle of "mutual recognition" to product standards

Explanation:

The major intention and purpose was for the Single European Act to have one market in place by December 31 of the year 1992. The act was proposed to effect the standards and principles of "mutual recognition" to product standards.

Which means that a standard developed in one European Community country should be acknowledged and accepted in another, as far as it meets the fundamental requirements in such matters as health and safety.