The process by which stem cells become specialized cells is called?
a.)elongation
b.)differentiation
c.)growth
d.)speciation

Which class of molecules contains the amino group, nh2 (a) sugars (b) water (c) proteins (d) hydrocarbons

In which situations is the principle of cross-cutting relationship useful in determining relative age?

Most of the fossils found in virginia are in the coastal plain, valley, ridge, and appalachian plateau regions, best suggesting that these geographic provinces a) were once covered by seawater. b) are the oldest parts of virginia. c) have a great deal of karst topography. d) have large amounts of sedimentary rock.