A baker who is familiar with the action of yeast in making bread rise suggests a way to use a gas-filled bladder to raise a ship from the bottom of a lake. The baker's reasoning is an example of which of the following?

The study of population numbers is called

gerontology. psychology. demography. geography.

If someone has the APOE-4 marker, this person:

A) is at much higher risk of getting Alzheimer's disease. B) will definitely get Alzheimer's disease. C) is at higher risk of getting vascular neurocognitive disorder. D) will definitely get vascular neurocognitive disorder.