In an Experiment, Knockout Mice Without the Ability to Taste

Multiple Choice

In an experiment, knockout mice without the ability to taste sweetness were conditioned over a period of six days. On the first day, they were allowed to sip from a sugar-water spout placed on one side of the chamber. On the second day, they were allowed to sip from a plain-water spout placed on the other side of the chamber. After the six days of conditioning, both spouts were made available again. The spouts delivered only plain water. The mice exhibited a strong preference for the spout that had previously delivered the sugar water. This implies that the mice had:

A) learned to recognize and prefer the nutritious sugar water.
B) developed the PAV version of a gene used to code for a specific taste receptor.
C) developed the AVI version of a gene used to code for a specific taste receptor.
D) regained their ability to detect sweet flavors.