True.
The earth is made of several subsystems or spheres that interact to form a complex and continuously changing (dynamic) state that is termed as the earth system.
Even though the earth system is a closed system, it self regulates through the subsystems such as the water cycle and carbon cycle.
The earth system is characterized by numerous overlapping cycles in which matter is recycled over and over again. Cycles involve multiple spheres and systems interactions. Humans impact and are impacted by the cycles in various ways.
An abstract is a summary of the most important points in a scientific paper so scientists can keep up to date and know what the scientefic work says with out spending lots of time reading it.
Check out the article below for more information.
Ebert, James R. "WHAT IS AN ABSTRACT." WHAT IS AN ABSTRACT<span>. N.p., n.d. Web. 06 Mar. 2016.</span>
Explanation:
By using sound absorbing substances we can reduce the echoes.
as we seen in the cinema hall...lol