Fill in the table “Internal structure of arthropods”.
| October 30, 2020 | Education
| Organ system | Structural features |
| Circulatory system | Open |
| Nervous system | Periopharyngeal nerve ring and abdominal nerve cord |
| Excretory system | Green glands in cancer, kidneys |
| Reproductive system | Male and female gonads |
| Digestive system | Mouth, pharynx, esophagus, stomach, intestines, anus |
| Respiratory system | Gills, pulmonary sacs, trachea |
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.