The role of structure A is to attract pollinators. Pollinators are the organisms which helps in the pollination of flowers. These organisms gets nectar from the flower. During their contact with flower pollens are attached to their body and when they moves to another flower these pollens falls on the carpel of the flower and as a result pollination occurs that leads to formation of seed.
Leaching is the process where dissolved nutrients in the
soil profile moves downward with percolating water. It is the loss of
water-soluble plant nutrients from the soil. The nutrients that seep through
the rooting zone may be recycled if roots grow deeper.