Which of the following statements is true about how species evolve? a. Species never change; they always stay the same.

b. Species change gradually, over many generations.

c. Individual organisms of a species can change during their lifetime to adapt to their environment.

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.