The present invention relates to genetic engineering of production microorganisms used in biotechnology to improve their properties so that they produce useful products more efficiently. The audio-transmission channel is adapted to the respective audio-spectrum of the speaker at predetermined intervals. Then, it provides an extremely flexible presentation mechanism where the content is organized by multi-dimensional mappings to present the information effectively. A time limited exclusive opportunity is awarded to one seller of the item to obtain from the interest group a commitment to buy the minimum quantity of items at the price per item as bid by the one seller. One of a radial outer portion and a radial inner portion of the variable airfoil includes a rotational shaft and the other of the radial outer portion and the radial inner portion includes a ball and socket joint that rotationally connect the first variable airfoil relative to the first platform and the second platform.