What is the null hypothesis in find the best mouse diet for weight gain

Some nutritionists claim that the secret to long life is to be slightly underweight as an adult. If a persons weight is related partly to diet, partly to activity level, and partly to genetics, what underlying factors could be at work to generate statistics that support this claim?

Describe Pavlov’s dog experiments as an example of classical conditioning.

Name three genes whose mutations lead to an altered behavioral phenotype. Briefly describe the normal function of the mutated gene as well as the altered phenotype.

Animal Models: The Search for Behavior Genes You are a researcher studying an autosomal dominant neurodegenerative disorder. You have cloned the gene underlying the disorder and have found that it encodes an enzyme that is overexpressed in the neurons of individuals who have the disorder. To better understand how this enzyme causes neurodegeneration in humans, you make a strain of transgenic Drosophila whose nerve cells overexpress the enzyme. a. How might you use these transgenic flies to try to gain insight into the disease or identify drugs that might be useful in the treatment of the disease? b. Can you think of any potential limitations of this approach?

For centuries, animal breeders have used artificial selection to increase the speed of racehorses. The results of such efforts are illustrated in a graph that identifies how quickly winning horses ran the 1-mile track at the Kentucky Derby, a famous race held annually at Churchill Downs, Kentucky. (The time it takes a horse to run a track of fixed length is inversely proportional to the horses speed.) Based on the data in the graph, has artificial selection increased the speed of horses consistently between 1900 and 2000? Do you think that artificial selection can increase the speed of racehorses in the future?