Ant said honeybees are important to plants because the bees help to spread the pollen. This is correct. Plants need their pollen spread from plant to plant to make seeds. These seeds fall to the ground and grow new plants. If we didn't have new plants growing, eventually all the old plants would die and wouldn't be replaced.
Some pollen is spread by the wind or other insects like beetles, flies and bees.
Notice in the picture below the pollen caught in the bee's hair. This pollen will fall on the next flower the bee lands on. In humans the circulatory system is confined in arteries and veins. She got this information on the internet. However, insects usually have one blood vessel that runs along the inside of its back.