Answer:
Nitrogen is present in the atmosphere in a molecule form about 78 percent. This nitrogen comes to the earth with the water through rainfall. Some nitrogen fix by beneficial microorganisms such as Cyanobacteria and Azotobactor which are present in the roots of higher plants. These microorganisms convert nitrogen molecule into nitrates and used by the plants. There are some other microorganisms which again convert nitrate into nitrogen molecules, called denitrifying bacteria and nitrogen molecule goes to the atmosphere again and complete the cycle.
Adenine and guanine have a fused-ring skeletal structure derived of purine, hence they are called purine bases. ... Similarly, the simple-ring structure of cytosine, uracil, and thymine is derived of pyrimidine, so those three bases are called the pyrimidine bases.
FALSE
All organisms use this "mechanism" to defend their food and shelter. Birds protect their nest just like all other animals and they fight for food.
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When the fertilized egg implants somewhere outside the uterus is called ectopic pregnancy
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the answer is d.pacific ocean is the largest ocean in the world it is also the world's deepest ocean.
