Explain how crop rotation and cover crops are important to sustainable agriculture.

There is a need for the farmers to implement a crop rotation, which builds or maintains soil organic matter, manages and conserves nutrients, works to control pests, and protects against erosion. The cultivators of perennial crops, which are not rotated may use some other kind of approaches like cover crops, in order to sustain the health of the soil.  

The cover crops like hairy vetch or clover, are grown at the time of off-season when the soils may otherwise be left barren. These crops build and safeguard the health of the soil by replenishing soil nutrients, preventing erosion, minimizing the need for herbicides, and keeping the weeds in check.  

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

hope this : )