Statement A: In hydrosere, free floating hydrophytes are replaced by rooted submerged hydrophytes.Statement B: Free floating hydrophytes do not allow the light to reach up to the submerged hydrophytes.

Submerged rooted hydrophytes are replaced by free floating hydrophytes because the free floating hydrophytes absorb the light that falls on the water body and make available little or no light reaching the submerged hydrophytes and gradually the submerged hydrophytes are eliminated and the surface of water body is with free-floating hydrophytes.