Important crop plant such as wheat and corn do not have useful relationship with rhizoba . Instead they rely on nitrates in the soil as a source of nitrogen . Fertilizers are used to increase the nitrate concentration of the soil and increase crop yield . Explain how crop rotation will help in this sitiuation

Crop rotation will help in fixing the nitrate in the agricultural field with the help of rhizoba bacteria

Explanation:

The crops of  wheat and corn do not have any relationship with the rhizobia which means they depend on soil for their nitrate requirement.  

Now Rizhoba interacts with the leguminous crops such as pulses to capture the atmospheric nitrogen and convert & store it as nitrates with in the roots of leguminous crops.  

Thus, in order to get nitrate from soil for wheat and corn crop, leguminous crop must be grown before these two crops in the field so that rizhoba fixes sufficient nitrate in the soil . In this way crop rotation will enhance the yield of wheat and corn

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!