2. Poems and songs are treasures of China traditional culture, many of which contain biological principles. The following poems are common in the relationship between living things: predation, competition, cooperation, parasitism, etc. "Flowers bloom all over the world in April, and peach blossoms begin to bloom in mountain temples", which shows that the environment affects the growth and flowering of living things. Every 1km above sea level, the temperature drops by about 6℃, so the temperature on the mountain is lower than that on the mountain. Peach blossoms in the mountains bloom later than those in the mountains, which is a natural phenomenon of "flowers bloom in April and peach blossoms bloom in mountain temples". Bean sprouts and grass compete with each other for sunlight, moisture, inorganic salts and living space. This is a competitive relationship; More grass means more water and inorganic salts absorbed by grass; Grass also occupied the living space of bean seedlings, blocked the sunlight, affected the photosynthesis of bean seedlings, and led to the slow growth of bean seedlings, so there was a scene of "grass full of bean seedlings". The main function of decomposer is to decompose organic matter in animal and plant residues into inorganic matter and promote the material circulation in nature. Therefore, bacteria and fungi play a major role in the process of transforming fallen flowers into spring mud.
So choose: B.