My response to your question is inexplicably being blocked from posting, so I've attached it as a PDF file. Please let me know if you can't access it or if you have any other follow-up questions/comments. Hope this helps!
It happens when the two groups become sufficiently different and the two can no longer interbreed. A known example of speciation is the London underground mosquito where it formed a new species within the existing genus. There are examples in micro-evolution but not in macro-evolution.
Humans are indeed still evolving, the way how we are evolving nowadays has changed slightly compared to how we would have been evolving had we not developed cities and the modern way of life and how we live. There are always adaptations going on and different selective pressures as well.
One parent with A and another with B can produce a child with A, B, AB or O blood types.
If one parent has A and another has AB, they can either produce a child with A, B or AB blood types.
Answer:
<h3><u>Required Answer</u><u>:</u><u>-</u></h3>
An increase in population, resources, natural disasters, and catastrophic events. Weather, natural disaster, human activity. As a population reaches its carrying capacity, resources become more scarce.