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In the 1960s, scientists found evidence that new material is indeed erupting along mid-ocean ridges. The scientists dived to the ocean floor in Alvin, a small submarine built to withstand the crushing pressures four kilometers down in the ocean. In a ridge’s central valley, Alvin’s crew found strange rocks shaped like pillows or like toothpaste squeezed from a tube. Such rocks form only when molten material hardens quickly after erupting under water. These rocks showed that molten material has erupted again and again along the mid-ocean ridge.
When scientists studied patterns in the rocks of the ocean floor, they found more support for sea-floor spreading. You read earlier that Earth behaves like a giant magnet, with a north pole and a south pole. Surprisingly, Earth’s magnetic poles have reversed themselves many times during Earth’s history. The last reversal happened 780,000 years ago. If the magnetic poles suddenly reversed themselves today, you would find that your compass needle points south.
Explanation:
I found this somewhere.
<span>Alleles are usually represented by three different methods using two alphabets; when the two alphabets are small letters, it means that both alleles are recessive; when the two alphabets are capital letters, it means that both alleles are dominant and when one of the letter is capitalized and the other a lower case, it means that one of the allele is dominant while the other is recessive. Genotype CC means that the two alleles for curly hair are dominant.</span><span />
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Normally, transcription begins when an RNA polymerase binds to a so-called promoter sequence on the DNA molecule. ... Some regulatory proteins affect the transcription of multiple genes. This occurs because multiple copies of the regulatory protein binding sites exist within the genome of a cell.
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Answer:
1-Mouth:the mechanical digestion takes place in mouth with the help of teeth. chewing is the machanical digestion of food in mouth.
2-Stomach: by the churning process. churning is the mixing of food in stomach by the movements of smooth muscles in stomach wall.
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