(1) The growth of red apricots is a manifestation of plant phototropism, because when plants are illuminated by light from one side, auxin is transported laterally to the backlight side, resulting in uneven distribution of auxin and backlight One side is more distributed than the side facing the light; and auxin can promote the growth of plants, so the plants appear to grow bent toward the light source.

(2) Falling red means that the flowers and leaves of plants fall off. Under the decomposition of soil microorganisms, the organic matter contained therein is decomposed into inorganic matter, which is then absorbed by the plant.

(3) The food chain includes both producers and consumers, so the food chain included is rice → pest → frog.

(4) "Hoeing" can not only loosen the soil, enhance the respiration of crop roots, and facilitate the absorption of mineral elements by the roots; it can also remove weeds and reduce competition between weeds and crops. , allowing more energy to flow to crops, thereby increasing crop yields.

So the answer is:

(1) Under the irradiation of light from one side, auxin is distributed unevenly. It is more distributed on the backlight side than on the light side, and the plant bends towards Light source growth

(2) Decomposer organic matter? Inorganic matter

(3) Rice → Pest → Frog

(4) ① In order to loosen the soil and strengthen crops The respiration of roots is conducive to the absorption of mineral elements by roots

②In order to remove weeds, reduce competition between weeds and crops, and allow more energy to flow to crops