<span> Because stem-cell therapies are relatively new and their side effects have yet to be completely discovered.
Long delays associated with the search for organ donors
Large payments to secure a bone marrow donor
Possibility that the organ may be rejected</span>
Uhm to be honest..
All types of exercise ask for oxygen to produce energy... so this is a bit confusing but it would be easier with answer choices:/
anyways have a good one:)
Dopamine which is responsible for transmitting signals between the nerve cells (neurons) of the brain.
