What trade item did the British introduced into Chinese to create a more balanced and trade between two countries A-cotton
B-tea
C-tobacco
D-opium

D

Explanation:

I think that is right

crop rotation kepy different plants in the soil instead of once constintly. when switching out plants you have different nutrients being absorbed at different speeds and different roots growing differently therfore the spoil and water flow have to adapt and carry fresh nutrients to carry the constant changes that were going on in the soil.