Answer:
the complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord.
Explanation:
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The right answer is A) Trisomy
Aberrant karyotypes containing an abnormal number of chromosomes are known in the human species. The best-known (and most common) chromosomal abnormality is trisomy 21, which is responsible for Down syndrome (mongolism). There are others such as Turner syndrome (woman with a single X chromosome) or Klinefelter syndrome (man XXY).
These abnormalities originate from the non-disjunction of the chromosomes of a pair of homologues during metaphase I of meiosis. At the end of division I, a daughter cell contains the two chromosomes of the pair considered and the other cell does not contain a chromosome of this pair. A similar result can be obtained during a bad distribution of chromatids during anaphase II.
After fertilization from a gamete of this type, a trisomy or a monosomy is obtained.
The answer is <span>They both suggest that snakes evolved from an ancestor with legs.
The second choice is not correct since we have no information about pythons and other snakes. We only have the relationship between geckos, snakes and legless eels. So, it is said that </span><span>snakes in general have more DNA sequences in common with four-legged geckos than they do with legless eels. This means that snakes are closer to geckos than the legless eels. We cannot conclude from this information which evolved from which, but we can say that </span><span>snakes evolved from an ancestor with legs.
In different case, if the snakes had more DNA sequence in common with legless eels, we would conclude that the snakes evolved from an ancestor without legs.</span>
The answer is Clean Water Act
Answer:
The functional groups that define the two different ends of a single strand of nucleic acids are:
B. a free hydroxyl group on the 5' carbon a free hydroxyl group on the 3' carbon
G. a free phosphate group on the 5' carbon
Explanation:
A nucleic acid is a polymer formed of nucleotides that are linked with a phosphodiester bond. The structure of a nucleotide consists on a phosphate group linked to a pentose (ribose in RNA and deoxyribose in DNA) that is also attached to a nitrogenous base. The nitrogenous bases are adenine, guanine, cytosine, thymine (in DNA) and uracil (in RNA).
DNA and RNA are nucleic acids which can be found in a double or single strand presentation.
Nucleic acids are synthesize in the 5’ to 3’ direction, so that is why the convention is that the sequences are written and read in that direction.
The strand of a nucleic acid is directional with an end-to-end orientation, where the 5’ end has a free hydroxyl or phosphate group on the 5' carbon of the terminal pentose, and the 3’ end has a free hydroxyl group on the 3’ carbon on the terminal pentose (ribose/ deoxyribose).
