In pavlov's classical conditioning experiment, he presented the sound of a bell along with meat powder to his dogs. after several trials, the dogs learned to salivate to the sound of the bell in the absence of the meat powder. in this study, meat powder acted as a(n)

In fruit flies, gray bodies (g) are dominant over black bodies (g), and brown pigments (n) are dominant over yellow pigments (n). each individual possesses two alleles for each trait. if a fly that is homozygous dominant for both traits is crossed with a fly that is homozygous recessive for both traits, what is the predicted genotype of the offspring.

Hector is back from his morning run and is feeling light-headed because his energy is depleted which food item will provide him with a quick source of carbohydrates

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.