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What is the origin of such a wide genetic variation among offspring?

In all the species that reproduce sexually, there are three main mechanisms that contribute to genetic variation:independent assortment of chromosomes, crossing-over, and random fertilization. Independent as...
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Answered by Andrew M. • Biology tutor
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I don't understand the difference between DNA, genes and chromosomes?

In the every cell of the human body, there is a part called the nucleus - this contains all of the genetic information. In each cell nucleus there are 24 pairs of chromosomes. They come in pairs because we g...
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Answered by Hannah I. • Biology tutor
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Different enzymes catalyse specific reactions. Explain why enzymes can only catalyse specific reactions.

A simple way of thinking about why enzymes catalyse only specific reactions is to think of the enzyme and the substrate (the compound the enzyme is acting upon) as a lock and key system. Enzymes have a parti...
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Answered by Oliver D. • Biology tutor
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What are the differences between DNA and RNA

There are 4 main differences, the first being that DNA is in a double helix structure much like two pieces of string wrapped together. RNA, on the other hand, is single-stranded. The second difference is in ...
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Answered by Arif A. • Biology tutor
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How do I answer questions on the adaptations of the lungs

Start by stating the function of the lungs: gas exchangenext go though the adaptations, with the number of available marks guiding the number of adaptations ~ 1 per mark Fick's law of diffusion states that: ...
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Answered by Justine S. • Biology tutor
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