Final answer:
The handshake between Yuan Longping and Song Yingxing is an imaginative scenario connecting the agricultural advancements across Chinese history, with Yuan being known for hybrid rice and Song for his scientific work during the Ming Dynasty.
Step-by-step explanation:
The question about why Yuan Longping shook hands with Song Yingxing appears to mix modern figures with historical contexts, possibly creating a fictional scenario for educational purposes. Yuan Longping was an agronomist known for developing the first hybrid rice varieties in the 1970s, a scientific discovery that had a significant impact on food production and security. Song Yingxing, on the other hand, was a scientist and engineer during the Ming Dynasty, remembered for his work 'Tiangong Kaiwu' which described various technologies of his time. Considering that these two individuals lived centuries apart, they never shook hands in reality. However, discussing a handshake across time and space as a symbolic gesture could represent a broader connection between historical and modern scientific advancements in Chinese agriculture and technology.