Why is the current system for the classification of organisms subject to change? A. New organisms are being discovered, and observations of anatomical similarities lead to the identification of these organisms.

B. Molecular evidence is being used to analyze amino acid sequences and other biochemical similarities, which allows for a more
precise comparison of organisms.

Which of the following is an advantage of using embryonic stem cells in medical research? a. the use of embryonic stem cells is much less expensive than the use of adult stem cells. o b. no living tissue is damaged when scientists use embryonic stem cells. o c. embryonic stem cells are able to differentiate into a wider range of cells than adult stem cells. d. there is no controversy surrounding the use of embryonic stem cells.