Only about (31) ____________of people over 65 become senile.A much more common problem is in fact caused by: (32) ____________.(33) ____________.Nearly (34) ____________of people over 65 has at least one serious illness. Maybe about 15% of older people suffer from (35) ____________.When people become old, there are changes in metabolism, lungs, the senses, (36) ____________and (37) ____________.