A. Design for Hope

B. Battle against Cancer

C. Donation for Patients

D. Decoration in Hospital

Plants are boring. They just sit there photosynthesizing （光合作用） while animals have all the fun. Right? Not so much. A new study has found that there is a long history of interactions between ants and plants. The ant and plant co-evolution （协同进化） started with ants feeding on plants and plants evolving ant-friendly features.

Plants make a number of different structures that are specific for ant use. Some plants have evolved features that persuade ants into defending them from attack from other insects and even mаmmаlѕ. Тhеѕе іnсludе hollow thorns that аntѕ will live іnѕіdе, or ехtra nесtаr (琼浆) оn lеаvеѕ or stems for the ants to eat. Some ants will just cheat and take the nectar and run, but some will stick around and attack anything that tries to hurt the plant. Other plants get ants to help them move their seeds around, by providing them with rich food packets attached to the seeds. The ant will pick up the seed and carry it away, eat the food packet, and leave the seed - often in a nutrient-rich area where it'll grow better, and since it's farther away from its parent, they won't have to compete for resources.

But scientists weren't sure how the evolutionary relationship between ants and plants got started. If evolution is an arms race between species developing ways to make use of their neighbors, then scientists wanted to know whether plants or ants fired the first shot. It was a chicken-and-egg question, whether things started with ants developing behaviors to take advantage of plants, or plants evolving structures to take advantage of ants.

The history of ants and plants evolving together goes back to the time of the dinosaurs, and it's not easy to tell from fossils who fired the first shot. However, it is a question of little significance. Scientists say their study maters because it provides a look at how these widespread and complex interactions evolved.

32. Some plants attach food packets to their seeds in order to .

A. reward the ants B. make a fool of ants

C. provide nutrition for the seeds D. get the seeds moved around

33. What does Paragraph 2 mainly tell us?