What were the major challenges of obama's first term?

The culture between conservatives and liberals, which continued into the twenty-first century, with abortion, affirmative action, gay rights and evolution provoking controversy. The Great Depression shook the economy, and Americans wondered how to deal with problems of health care, retirement, illegal immigration and the environment.

Hi! after fertilization occurs, the zygote goes through mitosis and then differentiation (aka specialization of cells) to have a variety of cells that perform different functions. this allows for the creation of tissues and so on, all of which were once stem cells with no specific function.i hope i !