This document discusses different types of pollination including natural pollination, self-pollination, and cross-pollination. Self-pollination involves the transfer of pollen within the same flower or plant and examples include pea plants and barley. Cross-pollination involves the transfer of pollen between different plants and is favored by adaptations like dichogamy and heterogamy. The agents of cross-pollination can be biotic, like insects, birds, bats, and ants, or abiotic, like wind and water. Cross-pollination provides advantages like healthier offspring and new varieties, while self-pollination risks weakening offspring over continued inbreeding.