Spiral galaxies have three main components: a bulge, disk, and halo (see right). The bulge is a spherical structure found in the center of the galaxy. This feature mostly contains older stars. The disk is made up of dust, gas, and younger stars. The disk forms arm structures. Our Sun is located in an arm of our galaxy, the Milky Way. The halo of a galaxy is a loose, spherical structure located around the bulge and some of the disk. The halo contains old clusters of stars, known as globular clusters<span>.
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Elliptical galaxies are shaped like a spheriod, or elongated sphere. In the sky, where we can only see two of their three dimensions, these galaxies look like elliptical, or oval, shaped disks. The light is smooth, with the surface brightness decreasing as you go farther out from the center. Elliptical galaxies are given a classification that corresponds to their elongation from a perfect circle, otherwise known as their ellipticity. The larger the number, the more elliptical the galaxy is. So, for example a galaxy of classification of E0 appears to be perfectly circular, while a classification of E7 is very flattened. The elliptical scale varies from E0 to E7. Elliptical galaxies have no particular axis of rotation.
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Answer) Model A shows the sharing of electrons, and model B shows the formation of ions.
Answer:
OPTUON C,CHEMICALLY BONDED
Answer : The correct option is, (B) 2, 3 and 6.
Explanation :
Combustion reaction : It is a type of reaction where a hydrocarbon react with an oxygen molecule to give carbon dioxide, water as a product.
In general,
For example : Ethane react with oxygen to give carbon dioxide and water.
In the given list, 
is a reactant and 
are the products.
Therefore, the correct answer is, (B) 2, 3, and 6
