Answer:
20%
Explanation:
There are four bases in DNA: guanine (G), cytosine (C), adenine (A), and thymine (T). They all have to add up to 100%. In DNA, guanine pairs with cytosine and adenine pairs with thymine.
If guanine is 30%, cytosine is also 30%.
30% + 30% = 60%
Now subtract from 100%.
100% - 60% = 40%
Thymine and Adenine make up 40% of the DNA. Now divide by 2 since there are two nitrogenous bases.
40% ÷ 2 = 20%
Guanine is 30%, Cytosine is 30%, Adenine is 20%, and Thymine is 20% for a total of 100% of the DNA.
Hope that helps.
