An isotropic indicatrix means: $($choose all$)$

a$.$ Velocity of light is different in different directions

b$.$ Absorption of light is different in different directions

c$.$ Velocity of light is the same in different directions

d$.$ Density of material is the same in all directions

Alligatorite $($a made$-$up mineral$)$ is in the orthorhombic crystal system. Please answer the following two questions about Alligatorite. You cut a sample of alligatorite into a cube. The density of atoms along the $c$ axis is

a$.$ The same as along the $a$ or $b$ axis

b$.$ Greater than along the a or $b$ axis

c$.$ Less than along the a axis but the same as along the $b$ axis

d$.$ Less than along the $a$ or $b$ axis

e$.$ None of the above

For the same cube of alligatorite, will light travel fastest along the $a,b,$ or $c$ axis.

a$.$ Light will travel the same speed regardless of whether it is traveling along the $a,b,$ or $c$ axis

b$.$ Light will travel fastest along the a axis

c$.$ Light will travel fastest along the $c$ axis and slowest along the $b$ axis

d$.$ Light will travel fastest along the $c$ axis and slowest along the a axis

What is the electrostatic valence bond strength

between Mg and O in olivine: $(Mg,Fe{)}_{2}Si{O}_4?37,40,41,$ and $43$ please