That the oxygen levels in the test tube increased and carbon dioxide levels decreased because plants produce oxygen using carbon dioxide
River water contains minerals and nutrients that can be beneficial to plants on the land, helping them to grow.
The genotypic ratio of the above cross will be 1:2:1, that is 1 homologous plant with axial flowers (AA), 2 heterozygous plants with axial flowers (Aa) and 1 homologous plant with terminal flower (aa).