Number (1) is shown in its stretched and contracted states. It has multiple bladders up the sides. Number (2) also has multiple bladders up the sides. Number (4) has a branching body with one weight and multiple bladders. Number (3) has a branching body with one bladder and multiple weights.
Reader Challenge: Since these organisms would likely have slow growth due to the limited energy available, what defenses should they have to keep from being eaten?