Health homework question

What is it called when a disease occurs in excess of normal expectancy? (more than expected)
A. A pandemic
B. An outbreak
C. A spread
D. An epidemic

Why do vivid images create more memorable memory

How does a bone marrow transplant treat sickle cell disease?

In multiple sclerosis, the immune system destroys the substance that coats and protects nerve fibers in the brain and spinal cord. this causes inflammation and injury to the nerves, and the axons don't conduct impulses as well.