So, we know that a metamorphic rock is either an igneous or a sedimentary rock that are exposed to intense heat and pressure.
But when the metamorphic rock is thrusted deep underground through subduction, it will again be subjected to intense heat. This can cause it to melt, turning it into a magma. When the magma cools down, it again becomes an igneous rock and the rock cycle continues.
Answer:
A= 20%
G= 30%
T= 20%
C= 30%
Explanation:
Recall that the sum of all nitrogenous bases in the DNA nucleotide is equal to 100%. And specific base pairings of Adenine to Thymine (A=T), and Cytosine to Guanine (C=G) must be equal.
So, the percentage of Adenine equal thymine, and that of cytosine equals guanine.
Now, A + T + C + G = 100%
So, if Adenine makes up 20% of the DNA nucleotides, Thymine is also 20%.
Then, 20% + 20% + C + G = 100%
40% + C + G = 100%
C + G = 100% - 40% = 60%
So, divide 60% by 2 to obtain the individual percentage of cytosine and guanine. Each will take 30%
Finally, A= 20%; G= 30%; T= 20%; C= 30%
It has been estimated that active tobacco smoking causes close to 90% of lung cancer cases and is the cause of 87% of lung cancer deaths.
Scientists are still doing research and we just need to be patient. :) :)