Answer:
Cyanobacteria, Anabaena and Azotobactor are called Nitrogen fixing bacteria. These bacteria change the nitrogen in the atmosphere into a form that is used by the plants to make proteins. Plants take nitrogen in the form of nitrates. The atmospheric nitrogen is first converted into ammonia after that ammonia is converted into nitrates and this nitrates use by the plants to make proteins.
Genetic variation<span> occurs </span>mainly<span> through DNA mutation, gene flow (movement of genes from one population to another) and sexual reproduction</span>
Answer:
There is no actual way that the mantle could be...'exposed' or 'seen'. But scientists have managed to find multiple ways to analyze the mantle and it's actual existence by using multiple devices. The mantle is basically a 2,900 kilometers (1,802 miles) thick blocks of rocks and minerals underneath the crust(or the surface of the earth) , and makes up a whopping 84% of Earth's total volume.
<span><span>Kingdom:Animalia
</span><span>Phylum:Mollusca</span></span>Class: Gastropoda
Symmetry: Bilateral
mantle<span> Is used for breathing and </span>excretion
Foot helps in locomotion
The visceral mass<span> helps in digestive, nervous, excretory, reproductive, and respiratory systems.</span>
Cephalopod belongs to the same phylum.
