Analysis of test questions: Algae plants are mostly distributed in 70% of the water environment on the earth's surface, and a few live in humid places on land. Algae plants are simple in structure, with no differentiation in roots, stems and leaves. Cells contain chloroplasts, which can produce organic matter and release oxygen through photosynthesis. 95% of the oxygen in the air is provided by algae. In spring, the temperature gets warmer, and algae plants multiply, making the water green. Bryophytes have no real roots, only false roots, which only play a fixed role. Generally, there are stems and leaves, but there is no conducting tissue in the stems and leaves, so the plants are shorter. Bryophytes live in humid environment, such as wet ground and shady walls, and often grow bryophytes densely. They are like furry green carpets. Common bryophytes are moss, gourd and so on. From the above, we can see that "the moss marks are in the upper order" in the poem.
Comments: This is a basic question. As long as we master the main characteristics of algae and bryophytes, combine the meaning of the question and carefully analyze the poem, we can answer this question.