Crop rotation improves the quality of soil because: Select one:
Soil is not loosened so less erosion takes place
Weeds and vegetation are allowed to grow
It prevents pesticides from affecting crops
Humans mess with natural processes
Different plants require different nutrients

2nd one

Explanation:

crop rotations with nitrogen fixing crops such as legumes and some cover crops, can help put nitrogen back into your soil naturally. this makes soil healthy and can increase yields

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.