Multiple sclerosis occurs at a very high rate in Africans and East Asians. is usually the result of a dominant gene. is associated with damage to the myelin of the CNS. is most common in very warm climates. all of the above

Multiple sclerosis is associated with damage to the myelin of the CNS.

Explanation:

Multiple sclerosis is a demyelinating disease that affects the brain and spinal cord.

It is characterized by distinct episodes of neurologic deficits separated in time, attributable to white matter lesions separated in space .

It is common at higher latitudes (1:1000 US, Europe)  

It's onset is any age, usually 20-40yrs; It occurs in more females compared to males at a ratio 2:1.

Myelin in CNS destroyed by immune cells (macrophages) and this leads to slow conduction which in turn leads to limb weakness/paralysis and loss of co-ordination.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.

the tricuspid valve is present between right atrium and right ventricle