The connective tissues of mammalian brain is called the meninges. There are three layers of this tissue. The outer layer is called the dura mater. The arachnoid is the middle layer and the pia mater is the inner layer of it.
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Before answering this question, we need to understand first that what a mutation is. <em>A mutation basically is a change in the DNA or genetic sequence of an organism that can significantly affect or not affect the function of a specific gene in organism. </em>
Now coming towards the question, yes ofcourse it is possible that a Norwar rats population carries a different genetic mutation than a population os same rats in Africa or any other region, Why? Because sometimes environmental factors of a certain area can cause the population of a region to undergo mutation (For example harsh UV rays) and the other population donot contains that mutation. This will cause a slight change in the genetic makeup of the population of rats of Norther America. However, if the changes in genetic makeup continues to happen in North American Norway rats, a time will come when they will be genetically very different from same rats in Africa and in this way they will become a separate or different specie, this phenomenon is called speciation.
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The correct answer is: [D]: "receives venous blood from the lower extremity" .
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<u>Answer</u>: A) Africa and South America only
As shown in the map, the fossil evidence suggests that Cynognathus lived on the modern day continents of South America and Africa. Thus, from this distribution and the fragmentation of the ancient landmass into today's continents, result in the distribution of Cynognathus offspring species also only within the continents of Africa and South America.