Answer:
Species are as specific as you can get. It is the lowest and most strict level of classification of living things. The main criterion for an organism to be placed in a particular species is the ability to breed with other organisms of that same species.
D. As salt water in the oceans.
Answer:
large ice masses,cold ocean water
Answer:
If a DNA strand has 17% Thymine (T) the percentage of the other nitrogenous bases will be 33% of Guanine (G), 33% of Cytosine (C) and 17% of Adenine (A), according to Chargaff's law.
Explanation:
The percentage of nitrogenous bass in a DNA strand can be established by knowing the percentage of one of the bases present in the molecule, in this case knowing that Thymine corresponds to 17% of bases.
DNA has the nitrogenous bases adenine (A), guanine (G), thymine (T) and cytosine (C). The bases of one chain are matched with the bases of another, according to the complementarity of the nitrogenous bases, where:
- <em>Adenine is complemented with thymine A=T</em>
- <em>Guanine is complemented by cytosine G≡C</em>
According to this, DNA molecule there is as much T as A, and an equal amount of G and C, and the percentages of nitrogenous bases can be calculated according to Chargaff's rule.
Chargaff deduced that<u> in a DNA molecule the ratio of purine:pyrimidine is 1:1, so there must be the same amount of thymine as adenine and a similar amount of guanine for the cytosine</u>, according to the complementarity of the bases.
Calculating the percentages, according to the law of the base pair, if in a DNA chain there is 17% of T, in the molecule there is:
- <em>A = 17 %</em>
- <em>C = 33%</em>
- <em>T = 17%</em>
- <u><em>G = 33%</em></u>
- <em>Total ..... 100%</em>
Answer:
This technique is called in-vitro fertilization.
Explanation:
In-vitro fertilization (IVF) refers to a form of assisted-reproduction technology in which the encounter of male and female gametes takes place outside the female organism (such as a human patient, in this case). IVF may be employed in several situations, including:
- Abnormalities in the female reproductive tract which impair the flow of the ovum into the uterine cavity (e.g. blocked fallopian tubes).
- Abnormally low sperm counts.
- Surrogate pregnancy.