Considering the hierarchical level of complexity, bix (2) would be organ.
Level of complexity of living organisms
The level of complexity of living organisms follows the order: cell, tissue, organ, organ system, organism.
The order is from the simplest to the most complex with the cell being the most basic unit of all living organisms.
Thus, starting from the simplest, what should be in box (2) will be organ.
More on levels of biological organization can be found here: https://brainly.com/question/6070269
