(1) No matter the evaporation of water in the culture solution or the transpiration of plants in the greenhouse, some water droplets will appear in the transparent plastic film, among which the transpiration of vigorous plants is the main one.

(2) Increasing sunshine during the day can enhance photosynthesis, increase the organic matter produced, reduce the temperature at night, reduce the intensity of respiration, reduce the decomposed organic matter, and generally increase the organic matter accumulated in vegetables and increase the yield. Farmhouse manure can decompose organic matter and produce carbon dioxide through microbial decomposition.

(3) As can be seen from the figure, the physiological process represented by [①] → [②] in the figure falls on the stigma, indicating pollination. In fig. 3, it can be seen that the pollen tube enters the micropyle and releases sperm after its end breaks. One of the sperm and egg cells fused into a fertilized egg, which will develop into an embryo in the future. Another sperm fused with two polar nuclei to form endosperm nucleus, which later developed into endosperm. This process is called double fertilization, which means fertilization.

Artificial pollination is often used in agricultural production to overcome the defect that pollination cannot be guaranteed because of insufficient conditions, so as to achieve the expected yield.

Soaking seeds with water before sowing is to provide suitable water for seed germination.

Comments: Students should not be afraid of difficulties when encountering such problems. Read it several times, understand the problems, and solve each problem one by one through the knowledge we usually accumulate.