What prevents a white dwarf from completely collapsing upon itself?
a) gravity
b)tightly packed protons
c)tightly packed neutrons
d) tightly packed electrons

this protocol provides a detailed procedure for nucleoprotein extraction from cultured cells and tissues in an efficient manner.

meteorologists would compare a new weather map with one 24 h old to see how fast a front is moving.

layer 3 is younger than layer 6.

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.