Which of the following scenarios can be classified as a negative feedback loop? increase in blood pressure to reduce heart rate
increase in testosterone to help increase a fight-or-flight response
increase in oxytocin caused by increased contractions
increase in platelet production to help increase blood clotting

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population.b) the separated population is small, and genetic drift occurs.c) the isolated population is exposed to different selection pressures than the ancestral population.d) different mutations begin to distinguish the gene pools of the separated populations.e) gene flow between the two populations is extensive.