a stomata is used for mining space
opening_of_stomata is opening_up. stoma is plant_part. opening_of_stomata is not positioning. opening_of_stomata is positioning. opening_of_stomata is not event. closing_of_stomata is event. closing_of_stomata is not positioning. opening_of_stomata is event. closing_of_stomata is positioning. closing_of_stomata is not event.