A.
If the climate boundary is transgressed, it may cause increased desertification (drying out of land), which in turn may cause a large loss of suitable agriculture land, which affects the land boundary.
B.
If the ozone layer boundary is transgressed, the climate boundary will be affected, as increased stratospheric ozone depletion will warm the planet faster.
C.
If the ocean acidification boundary is transgressed, it may affect the climate boundary because phytoplankton will process the acidic ocean waters differently and release additional carbon into the atmosphere, which will in turn affect the aerosol loading boundary.
D.
If biodiversity loss increases even further, the ocean acidification boundary will be affected, as there are less species that can directly decrease the acidity the oceans at the global scale.