What is the sentence describing the tenacious vitality of weeds in Xia Yan's Weeds?

Xia Yan's essay, written in the middle of War of Resistance against Japanese Aggression, is intended to encourage people to strengthen their confidence in the victory of the Anti-Japanese War and use symbolic means. Weeds are used to symbolize tenacious vitality. Since Xia Yan, Bai Juyi has had "boundless grass that comes and goes with the seasons". Wildfire never completely burned them, but they grew tall again in the spring breeze. "Lu Xun has a famous poem" Wild Grass Inscription ". Xia Yan's new contribution lies in making the symbolic image of Weeds more complete, giving it a wider symbolic meaning and shaping a new artistic conception. First of all, the author uses strong contrast to show that weeds are a huge and unparalleled force without being noticed. On the one hand, it is a dense and solid skull that cannot be completely separated by any mechanical force, on the other hand, it is an ordinary seed; On one side are the dense boulders lying on them, and on the other side are the seemingly weak grass: the result of mutual struggle is the victory of seeds and weeds, the bones are cut and the boulders are overturned. Weeds are a "terrible force" for giants such as bones and boulders. This is the first point that the author wants to tell us. Secondly, the author analyzes that the reason why Weeds is so powerful is its "toughness". This is a growing and expanding vitality. It does not seek a quick victory, but it can "fight for a long time." I won't stop until I reach my goal. In this way, it will make all powerful enemies look weak and small. Thirdly, the author analyzes the optimistic spirit of Weeds. No matter how bad the growth conditions are, they will not be pessimistic; It has an innate struggle, which is more vigorous because of being tempered; It is full of confidence in its future. The power of weeds is a powerful, resilient, optimistic and promising force. This personalized weed perfectly, completely and aptly symbolizes the bright future of our great Chinese nation and the sacred national war that is persisting in the "long-term war of resistance". While eulogizing the national spirit through Weeds, the article also exposes and satirizes the dependence, weakness and compromise of the Kuomintang government in the Anti-Japanese War through the "potted flower" that can't cover the wind and rain, needs special care and plants, and lives in a glass shed. In order to keep consistent with the simple image of Weeds, the sketch adopts simple writing, does not carve, and tries to avoid beauty. It seems to be a chat at the beginning, which is intended to contrast, which naturally leads to the following, and finally ends with a "laughing" potted flower, which is natural and neat.