SORU: boş bırakılan yere parçanın anlam bütünlüğünü sağlamak için getirilebilecek cümleyi bulunuz
The cause of the immeasurable loss of memory and concentration that come with normal ageing is still shrouded in mystery.----. This is known and explains the disease. But there is little evidence for the death of neurons in healthy people as they age.