When blood moves around the body, it
A. Circulation
B. Pumping
C. System
D. Circulates

D. most models represent a real world object in a simpler way

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).

Ican't see the chart but the density of both nickel and cobalt is 8.90 g/cm3, so it would be one of those.