Which cover physicians who spend prolonged periods of time without direct patient contact, until physician's services are required?

The principle of opposition means that Yin and Yang:

A) Control and restrict each other B) Cannot exist in isolation from each other C) Are infinitely divisible D) Are constantly transforming into each other

Human embryonic ____________ cells are the building blocks of life. Early in pregnancy, they begin to differentiate into all the body's specialized tissues and organs

a. germ b. stem c. regenerative d. heterozygous