Pollination in cereal and vegetable crops depends on external agents called pollinators. Cereal crops like wheat, maize, and rice adopt wind pollination. Their pollen grains are light and small, produced in large numbers, and their stigma is long and feathery to trap them. Wheat flowers even open after pollination.

Vegetable and other crops like sunflower, hibiscus, and marigold are insect-pollinated by bees and butterflies. These flowers are brightly coloured, produce nectar, and emit fragrance. Their pollen grains are large, sticky, or spiny to attach to insects, and the stigma is sticky. Some plants, like the coral tree and hibiscus, are pollinated by birds such as sunbirds and the Indian white-eye. Aquatic plants like Vallisneria and Hydrilla use water pollination, where currents carry pollen. Specific crops have unique strategies; for instance, papaya trees often bear male and female flowers on different trees, while tomato flowers have stamens covering the stigma.

The provided context does not list specific reasons for the declining population of pollinators or their solutions. Instead, it instructs students to interact with farmers and observe pollinators visiting the school garden. By noticing and recording pollinator activity, taking pictures of at least five different types, and compiling data, students can identify local reasons for the decline and discuss appropriate solutions based on their field survey and class discussion.