This is the sign map of Fuzhou subway. The pattern is green, and the banyan tree is integrated as a tree in Fuzhou. The pattern consists of two parallel rails and three semicircles, which surround the rails to form a big banyan tree. It can be seen that two vertical lines are shaped like iron and three semicircles represent Fuzhou. In addition, according to the shape and background color of the tree, we can analyze the meaning of environmental protection, and according to the above analysis, we can answer this question.

Reference answer:

The figure consists of two parallel tracks and three semicircles, and the three semicircles surround the tracks to form a big banyan tree. The track represents the subway and the banyan tree represents Fuzhou, which means that Fuzhou subway is fast, convenient and green.