Chapter 121 opens with a description of the strange plants that have been discovered in the forest. They are the same plants that we've seen before in this chapter, and they're also the same ones that we saw in the beginning of this chapter. The group is trying to figure out how to get to the other side of the tunnel. The rail on the opposite side has broken down, so they can't get all the way there. The question now is whether the tunnel will reach the other end. The men decide that they'll go to the gym first, and then the rest of the group will go down to the tunnel, where they can use the rope that's attached to the shaft to pull them down. They decide that the first person to go down will be the man who sprained his foot in the accident, and the second person will go first because he's so manly. Okay, now that the men have figured out who's going to go first, it's time to talk about the weird plants. The first guy to come down is Sengoku, who is confused by the strange looking plants. He's not sure what to make of them, but he knows that they must have something to do with extinct animals. He also knows that the plants must have some kind of photo-synthesis, which is a chemical process that allows plants to produce sugars and carbon dioxide from light. This means that these plants must be living in the dark, which means that they don't have any light at all. The only thing that they can do is produce small amounts of carbon dioxide and carbo-hydrates, which are the