In a sample of double-stranded DNA, 30 \%30%30, percent of the nitrogenous bases are adenine (A). What percentage of the nitrogenous bases in the sample are thymine (T)?

The number of thymine (T) should be the same as adenine(A). That means we have 30% A and 30%T. 100-30-30=40%(G and C). Guanine(G) and cytosine(C) are also equal in number so we have 30%A(adenine) 30%T(thymine) 20%G(guanine) and 20%C(cytosine)

i'd say that the moon rock is about 2.2 billion years old.

the framers of the constitution insisted that federal judges be nominated instead of elected due to their desire to have judges above the shifting whims of the masses.

the hope, whether achieved or not, was that federal judges would only be beholden to the law and that by not having judges be elected, they would be protected if that law dictated an outcome that ran counter to popular opinion.