Which structure allows gases and nutrients in
and out of the cell?
A. mitochondria
B. cytoplasm
C. nucleus
D. cell membrane

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.

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important

What advantages does a pedigree have over a written passage?