A heterogeneous mixture composes of non- uniform components, so the concrete would be the answer, because you can tell the components from one another.
Substrate Concentration I believe
Botox injections comprise Botulinum toxin and is used in the treatment of some kind of eye ailments, like strabismus (crossed eyes) and blepharospasm (involuntary blinking), to treat movement disorders (like torticollis, cervical dystonia) or muscle spasms/stiffness. It can also be used to minimize the cosmetic appearances of wrinkles.
However, due to certain side effects, the drug was ban by FDA, but it has been approved by the FDA for treating spasms of the flexor muscles. Although, there is a scenario that the claim for the application of the drug could be rejected in case of a lack of a medical necessity, that is if it does not fulfil the usual accepted professional medical standards of care.
It is an example of migration. Hope this helps!
