Studies in which the suprachiasmatic nucleus (scn) was surgically removed from laboratory mammals demonstrated that the scn is required for circadian rhythms. but these studies did not reveal whether circadian rhythms originate in the scn. to answer this question, researchers performed an scn transplant experiment on wild-type and mutant hamsters (mesocricetus auratus). for wild-type hamsters, the period between cyclic peaks in activity is 24 hours in the absence of external cues. hamsters homozygous for the τ (tau) mutation have a period lasting only about 20 hours. in this exercise, you will evaluate the design of this experiment and propose additional experiments to gain further insight. the researchers surgically removed the scn from wild-type and τ hamsters. several weeks later, each of these hamsters received a transplant of an scn from a hamster of the opposite genotype. these transplants restored rhythmic activity in 80% of the hamsters. for hamsters in which an scn transplant restored a circadian rhythm, the researchers measured the circadian period. the results are shown in the graph. each red line represents the change in the measured period for an individual hamster. part a - understanding the experimental design in a controlled experiment, researchers manipulate one variable at a time. what was the experimental variable in this study?

picture a world where computers are building made-to-order personalized robotic arms and synthetic organs, drones are circulating above mars! due to the rapid growth of technology, the future has never been more unpredictable, and it presents a huge challenge in education: we are teaching students how to work in a future that we have never been unsure of. it is widely predicted that in eight years’ time, there will be more jobs in the fields of science, mathematics, technology and engineering than in any other discipline. and, as the technology continues to develop, it will soon become clear that addressing social problems will involve more innovative thinking, and analytical and technical knowledge than ever before. undeniably, there are no subjects that encourage innovative and creative thinking, deep thought, problem solving and independence more than the stem subjects. while it is widely commented on that there is a need to reimagine the ways stem subjects are taught in schools by embracing a more interactive and innovative approach to appeal to more students, it should come as no surprise that some of the most reputable educational organizations in the world are already implementing changes to embrace stem. harvard, for example, announced in 2014 that they were increasing their computer science faculty by over 50% and has since introduced computer science as a core subject for all freshmen. the urgency of supporting stem subjects at a young age is becoming more relevant than ever, as adopting a keen interest in the curricula needs to happen early. however, beyond the age issue is one of gender.

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