Answer:
Coal is mined in two different ways: from deep underground and in
strip mines. In both cases the land that is mined is leased by the coal companies, while the ownership remains in public hands. Deep mines are reached through a shaft into the ground, through which miners gain access to the coal seam and out of which comes the coal. Strip mines are used when the coal seam is near the surface. The topsoil and other overburden materials are removed by giant power shovels and piled out of the way. The shovels then dig out the coal. After the coal has been mined, there may be environmental reclamation to return the land to its original state, thus allowing others continued use of it for their own purposes. This involves refilling the hole, spreading topsoil, and then planting new vegetation on it.
Answer:
New cells are spontaneously created from existing cells
Explanation:
In the 1830's, three scientists namely: Matthias Schleiden (a botanist), Theodor Schwann (a zoologist) and Rudolf Virchow proposed the Unified cell theory. In this theory, three parts were universally accepted and they are as follows:
1) Cells are the fundamental and basic unit of all life and structure.
2) All living organisms are made up of one or more of these cells.
3) New cells arise from already pre-existing cells.
These three parts are the widely accepted parts of the cell theory. Although, it was once believed that new cells arose from inorganic matter. This theory, called spontaneous generation or abiogenesis was later disapproved.
Therefore, the statement that, "new cells are spontaneously created from existing cells" is not a part of the CELL THEORY.
Answer:
Natural selection
Explanation:
This is a form of natural selection because only the strongest will survive and reproduce making more resistant insects as the chain goes on.
Dna is double stranded
rna is single stranded
sugar in dna is deoxyribose
sugar in rna is ribose
nitrogenous bases in dna are adenine thymine guanine and cytosine whereas rna has uracil instead of cytosine
dna stays in the nucleus
rna leaves the nucleus