As early vertebrates transitioned from an aquatic lifestyle to terrestrial habits, major changes in structural and physiological characteristics facilitated their survival and expansion. It is likely that some of these traits are a result of: a) changes in developmentally important genes, as in evo-devo the ability of some cells to incorporate environmental DNA, or eDNA, into its genome b) new Hox genes that reverse some steps in development c) transcription factors that originate outside of the developing embryo d) new interactions between cytoplasmic determinants and the nucleus

Option-(A): The changes in developmentally important genes, as in evo-devo the ability of some cells to incorporate environmental DNA, or eDNA, into its genome              

Explanation:

The term evolution gets to play the most important role when we evaluate the conditions faced by the different organisms when the shifted from the aquatic form of life towards the terrestrial as there were more to perform for there body system and it all just did not happened in a day or two but it took millions of years of evolution inside the living beings to make them able to live on land. As, the genome of the different species was greatly changed and thus there cellular structures were made to defend the body from any foreign object and make it able to survive on land as well, just because there is difference of oxygen level and other natural resources inside the different spheres and for that some of the changes inside the cellular structures were required to be done.

answer; i believe that the correct answer is (lung);