A robin flying south for the winter
Answer:
Plants have evolved several adaptations to life on land, including embryo retention, a cuticle, stomata, and vascular tissue.
Here you go !
The definition of vestigial organs are rudimentary structures in humans
that correspond to a functional structure or organ in an ancestor.
Basically the answer is redundant organs present in an organism, which
have been functional in the organism's ancestors.
Answer:
your answer is b cells are white blood cells that work by producing antibodies, whereas t cells attack foreign invaders directly.
Explanation:
flashcards
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.
