A student wants to know why sandhill cranes fly south for the winter. The student uses a map of North America to
make a model of the paths sandhill cranes take as they
migrate. The student draws lines with arrows to show the
routes sandhill cranes are known to take.
Which two issues describe limitations of the student's model?
I A. It does not explain how migrating birds affect trees.
OB. It does not explain why the cranes fly south.
C. It does not show the paths of other migrating bird species.
D. It does not show when the cranes arrive at each location.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b