In a sea cucumber cultivator, sea cucumber cultivation baskets are arranged in multiple layers within a housing to protect the sea cucumbers from the external environment, to enable mass production and easy management of sea cucumbers. A second set of rollers is mounted along axes which are arranged 90 degrees relative to the first set of rollers and underneath the drawer. A bracket is slidably mounted to the movable rail and is movable along a sliding direction between a retracted position and an extended position. The second gate layer extends over the drain of the transistor above the dielectric and gate oxide layers to form the gate extension.