Demetri's experiment to explain why the color changed on some test strips but not others.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.

the answer to the blank provided is “an autosomal gene that is required for the expression of genes on the x chromosome”.

testis-determining factor, abbreviated as td, which is more popularly known as sex-determining region y or sry protein, is a dna-binding protein or  gene-regulatory protein/transcription factor, encoded by the  sry gene. it is the gene responsible for the initiation of male gender determination in humans.