In 1987 a group of molecular geneticists at the University of California at Berkeley offered support for the idea that modern hu
mans (AMHs) arose fairly recently in Africa, then spread out and colonized the world. The geneticists analyzed genetic markers in placentas donated by 147 women whose ancestors came from Africa, Europe, the Middle East, Asia, New Guinea, and Australia. By estimating the number of mutations that had taken place in the mithochondrial DNA (mtDNA) of each of these samples, the researchers concluded that...... A. everyone alive today has mtDNA that descends from a woman (dubbed Eve) who lived in sub-Saharan Africa around 200,000 years ago and that her descendants left Africa no more than 135,000 years ago.
B. everyone alive today has mtDNA that descents from a woman (dubbed Eve) who lived in Asia aorund 50,000 years ago and that her descendants left Asia 100,000 years ago.
C. establishing a "genetic clock" to model human evolution is reliable only when focusing on 50,000 years into the past.
D. everyone alive counts Neandertals of western Europe as their ancestor.
E. Neanderthals coexisted with modern humans in the Middle East for the least 2,000 years.
mtDNA is inherited from the mother of a child, this is because mitochondria are in the cytoplasm and the father's gamete (sperm cell) contributes very little or no cytoplasm to the zygote. We know that mitochondrial Eve came from Africa because the mutations in the mtDNA occurred before the <em>out-of-Africa dispersal</em>.
I believe that in this community the tadpoles are: the primary consumers. A n ecological community is the set of all populations of all species found in a given place. Primary consumers are mainly herbivores which feed on plants; which are the primary producers of all the energy in an ecosystem. In this case the tadpoles eat algae (primary producer) thus they are primary consumer.
Antibiotics killed the bacteria that cause infection but they can also kill beneficial bacteria . thus Ms ABC developed a yeast infection and diarrhea after course of antibiotics because antibiotics distrub natural balance of beneficial bacteria in her intestine.
