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Answer:
A protoplanetary disk is round rotating object which is made of dense gas. This surrounds the newly formed star, Herbig star and T tauri star.
It is also considered as a accreation because the remnants like gases and other materials fall from them on to the star.The extremely illuminating protoplanetary disk are known as the proplyds.
Whereas the nebula can be defined as the densely packed hydrogen and other gases that collapse under the force of gravity. The Nebula starts becoming smaller and smaller because the particles of gases collapse and get closer to each other.
Upon force of gravity their friction and heat increases which slowly collapse the star.
Answer:
There are four major classes of biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids), and each is an important component of the cell and performs a wide array of functions. Combined, these molecules make up the majority of a cell's mass.
Option C - They show that the number of atoms of each element is the same in the products and reactants.
The conservation of mass essentially states that no matter can be created or destroyed. It is because of the conservation of mass that we have to balance chemical equations in order to ensure than no atoms are destroyed or created.
-T.B.
The decomposers are at the end of the food chain..
Explanation:
Because, decomposers are the last orgainsms that depends and decomposes all other organisma in the food chain..
