Why do people of both jewish and christian faith trace the start of their religions to isaac?

a. they believe isaac is god's final prophet.
b. they believe moses and jesus are isaac's descendants.
c. they believe isaac wrote the old testament.
d. they believe isaac survived in the desert due to the of god.

   B. They believe Moses and Jesus are Isaac's descendants

Explanation:  Isaac is the second son of Abraham, whom he received with his wife, Sarah, after the visit of God and the promise that Sarah will bear his son, who will be an ancestor to the chosen people, and who inhabit the earth as a sand in the wilderness. Isaac had two sons, Esau and Jacob, of whom Esau was older, and he needed to receive a blessing for the heir, i.e. one who will extend the blessed line. However, Jacob bought the blessing from Esau for a meal, and with the help of his mother, Rebecca, he was able to receive the blessing from father Isaac'. Thus Jacob became an ancestor of the chosen nation, and he had twelve sons, of whom they became twelve tribes of Israel. Thus, Isaac is indeed the ancestor of all Jews, including Moses and Jesus Christ.

it increase by 12% a year from 1812-1820

answer:   migrations were important in the neolithic period. "two major migrations passing through southeastern europe were confirmed by the means of archaeo-genetic studies."

the first migration was the early neolithic period -- 6,000 before common era (bce) -- when the first farmers, from anatolia -- asia minor -- spread through europe. the second migration occurred during the early bronze age (3,000-2,500 bce) when the so-called "steppe population," from the eurasian steppe, replaced much of northern europe's previous population.

the first farmers of northern and western europe passed through southeastern europe with limited hunter-gatherer genetic admixture, which occurs when two or more previously isolated populations begin interbreeding. however, some groups that remained mixed extensively -- without the male-biased, hunter-gatherer admixture that prevailed later in the north and west, according to latest discoveries. southeastern europe continued to be a nexus between east and west, with intermittent genetic contact with the steppe people up to 2,000 years before the migrations that replaced much of northern europe's population.

"in some places, hunter-gatherers and incoming farmers seem to have mixed very quickly," says iain mathieson, a geneticist at the university of pennsylvania, who was first author of the paper. "but, mostly, the two groups remained isolated, at least for the first few hundred years. these hunter-gatherers had been living there for thousands of years, and it must have been quite a shock to have these new people show up -- with a completely different lifestyle and appearance."