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:
The following are the achievements of the Olmec
civilization:
1.
Water Drainage
-
This civilization was able to construct an
extensive drainage system that is made up of conduits. This was discovered by
the archaeologists in the town of San Lorenzo, the largest city of Olmec
cities. These was carved into a U type shape and covered by capstones. This was
believed to be used as aqueduct to provide water throughout the cities.
2.
Calendar system
-
It was discovered that Olmecs have their own
calendar system. They are using shells to represent numbers in their calendar which
starts with zero. This is one of the first uses of zero as starting point of a
number.
3.
Ulama
-
This is a game of the Olmecs with the objective
of knocking the ball through the hole with the use of hips. The sap of a rubber
tree was utilized to produce balls that was used before.
4.
Writing system
-
They are usually credited as one of those
civilizations to be the first to have their own writing system in America. Their
writing is mostly symbols rather than letter representation.
5.
Compass
-
They are the one to first create compass that
existed in America with the basic understanding of gravity and magnetism.
The answer is the second
one.
Deforestation of rain and forests and other parts of the world volcanic eruptions and widespread forest fires.
This activity has contributed greatest amount of carbon dioxide into the atmosphere over the past 100 years.
