Answer:
The spectral types and sub-classes represent a temperature sequence, from hotter (O stars) to cooler (M stars), and from hotter (subclass 0) to cooler (subclass 9). The temperature defines the star's "color" and surface brightness. ... Stars are also classified by luminosity class.
Explanation:
<span>Erosion by rivers is a main valley-forming
process; other processes, such as movement of the earth's crust and
glaciers, also have an important part in some cases. The rate at which a
river deepens its valley depends on several factors.</span>
Answer:
Shale.
Explanation:
It is composed of silt or clay that has been compacted or squeezed together to form a solid rock.
Longitude is the measurement east or west of the prime meridian. (Imaginary lines that run around the Earth vertically. up/down.)
The Balkan nations are currently capitalist, not communist, so the first statement is correct. Further, they do have internal conflict, for example between the Bosniak and Serbian population in Bosnia. They also attract foreign investment.
So all the options are correct!
