Questions

The support cells of the nervous system are Glia, also called glial cells or neuroglia. In the central nervous system, there are four types of supporting cells. They are ::

* Astrocytes

* Microglial cells

* Ependymal cells

* Oligodendrocytes

Africa - 54 countries

South America - 12 countries

Antarctica - 0 countries

Europe - 43 countries.

Hence, Antarctica continent has the least countries.

Genes: The DNA is the genetic material. The DNA is made of several nucleotides. A nucleotide means, one nitrogenous base one sugar molecule and a phosphate molecule. These Nucleotides occur in sequences and several nucleotides form one gene ( a functional gene is called a cistron)

Generally, plants absorb dissolved nitrates from soil and convert them into free nitrogen.

• Free nitrogen is simply molecular nitrogen (N2).

• Nitrogen, in its molecular form, consists of two nitrogen atoms bound together with a triple bond.

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