Answer:
It is the biological concept of species
Explanation:
In 1970 Mayr stated that "species are formed by groups of potentially intercrossing populations that are reproductively isolated from others". The biological concept of species puts emphasis on existence of barriers that limit the gene flow among groups within the same species
This would be considered the synaptic cleft
Answer :Erwin Chargaff a Biochemist
Explanation:
He formulated the base paring of double helix of DNA. He reasoned that since the percentage of four DNA bases are of this proportions in human;
Adenine=30.9% and Thymine =29.4%;
Guanine=19.9% and Cytosine =19.8%
Then, the amount of adenine will always be equal to thymine,
And the amount of Guanine equals to cytosine based on this percentages of distribution.
(Adenine and Guanine are large, molecule of Purines, while thymine and Cytosine are Pyrimidine)
He concluded (although scientist believed, he did not explicitly stated this) that this should be the base paring patterns in DNA molecule. This is the first Chargaff Rule.
His second rule is that the DNA composition, in the relative amount of the four bases Adenine, Thymine, Cytosine and Guanine varies in proportion from one organisms to another. And this is the basis of molecular diversity.
We feel hotter in summer than in winter because the temperature is generally higher than in winter.
<h3>
What are seasons?</h3>
There are three seasons on earth namely winter, summer, and rainy season. In the winter season, the temperature is cold and during summer the temperature is higher.
Timing and characteristic of season depend upon the location of the earth. The time of a year region experience season depends on it is northern hemisphere or southern hemisphere.
The southern hemispheres experiences winter while northern hemisphere experiences summer. The cycle of seasons is caused by earth's tilted towards the earth. The planet rotates around an axis.
Therefore, We feel hotter in summer than in winter because the temperature is generally higher than in winter.
To learn more about seasons, refer to the link:
brainly.com/question/19009677
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