Down syndrome is a chromosomal disorder which is caused by the presence of extra copy of chromosome 21. Therefore also called as Trisomy 21.
Alzheimer's disease is a most common form of dementia(reduction in brain functioning). It is caused by mutation in single gene APP (Amyloid Precursor Protein) present on chromosomer 21.
D, The cell take in water and food some of the food dissolve to create other things for the cells and they have structures that perform to help us survive.
