If 30% of the bases in a particular DNA molecule are guanine (G), what percentage of the bases would be thymine (T)? Explain your reasoning.

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.

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?