<prompt> Which of the following statements about Alzheimers disease are true?Onset before 45 years of age is rareLong-term memory is affected before sho term memoryStaining shows Tau protein in senile plaquesMRI shows atrophy in frontal and parietal lobes  <response>: The first statement is correct. Onset is usually after 65 years of age. Second statement is incorrect, long-term memory gets affected in advanced stages only. Third statement is also incorrect as senile plaques contain amyloid bet Ab and not tau proteins. The last statement can be argued upon. Alzheimers disease is usually described as disease of temporal and parietal lobe and MRI usually shows atrophy in temporal and parietal lobe. Although we must remember that frontal coex does get involved in the advanced phases 