Dr. calvin is giving a lecture on the properties of cardiac tissue. during the lecture, he states that the conduction tissue of the heart does not require any external stimulus to initiate its contractions. it has the ability to initiate its own electrical stimulation. to demonstrate this property, dr. calvin dissects a frog and places its heart in a petri dish with ringer's solution. he then asks his students to observe how the frog's heart continues to beat without any external stimulation. based on the information provided in this scenario, which property of the heart is dr. calvin trying to demonstrate?

answer; i believe the answer is (polygenic inheritance;

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

the answer is 95 degrees