When you arrive to the scene of an injury where the victim is unconscious, why should you not move them?

and you need a medical degree to do any thing or else you can go to jail.  

Explanation:

i think it because equal matrices have equal dimensions, only square matrices can be symmetric. for all indices and . every square diagonal matrix is symmetric, since all off-diagonal elements are zero. in linear algebra, a real symmetric matrix represents a self-adjoint operator over a real inner product space.

c)as speed changes, wavelength and frequency change.

everything changes!