Final answer:
Pine trees are monoecious, meaning they have both male and female reproductive structures on the same tree. Pollen from male cones fertilizes eggs in female cones, leading to seed development.
Step-by-step explanation:
Pine trees are monoecious plants, which means they have both male and female reproductive structures on the same tree. The male cones, or staminate cones, produce pollen grains that contain sperm cells. The female cones, or ovulate cones, contain ovules where the eggs are produced. When the pollen lands on a female cone, fertilization occurs, and the zygote develops into an embryo, resulting in seed development.