Which of the following is true of embryonic stem cells but not of adult stem cells?
a) they can differentiate into many cell types.
b) they make up the majority of cells of the tissue from which they are derived.
c) they can continue to replicate for an indefinite period.
d) they can provide enormous amounts of information about the process of gene regulation.
e) one aim of using them is to provide cells for repair of diseased tissue.