Scientists discovered that the difference between blond and dark hair comes down in part to a single nucleotide difference in the DNA sequence of an enhancer that lies more than 350,000 base pairs away from the gene it controls. On average, blonds transcribe this gene less efficiently than people with dark hair. How can a tiny difference in a distant enhancer make a blond?

The answer is given below.

Explanation:

A tiny difference in a distant enhancer make a blond through DNA Looping.

DNA Looping can bring the enhancer bound by an activator physically closer to the promoter even if the enhancer is located far away along the DNA molecule.

DNA Looping.

When a protein or a set of complex proteins binds to 2 different sites of DNA simultaneously while looping out the interfering DNA.  

Important of DNA Looping

It regulates metabolism of DNAit is involved in transcriptional initiation of prokaryotic operons.

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

carbon 14 dating is used to determine the age of the sample by estimating the amount of carbon 14 present in the sample and then comparing it with a reference standard.carbon 14 is a isotope of carbon which is radioactive and unstable. carbon 14 is assimilated by all plants and animals throughout their life from carbon dioxide. however, one the organisms die they stop this assimilation and the carbon 14 content starts to decrease.by knowing how much of carbon 14 is left in an organism after his death, one can estimate the age of the organism. the materials whose age can be estimated by carbon 14 method are the organic compounds. however, some inorganic compounds such as aragonite   shell can also be dated.however, if we consider the igneous rocks it is a non living component which never accumulated carbon 14 in it and thus, we cannot use carbon 14 dating method to estimate its age.