Answer:
four phenotypes appear in the ratio 9:3:3:1
Explanation:
<em>For a dihybrid cross in which the two genes concerned obey simple dominant/recessive law and are independently assorting, </em><em>four phenotypes are produced in the ratio 9:3:3:1. </em>
The dominant gene takes up the largest ratio (9/16) while the recessive gene takes up the smallest (1/16). Any deviation from 9:3:3:1 and the number of phenotypes produced from a dihybrid cross is an indication that the genes involved do not obey Mendelian laws.
Okay, biology isn't exactly my strongest subject (it never has been), but I'm pretty sure the answer is nucleotides. DNA is made up of nucleotides. Each nucleotide contains a phosphate group, a sugar group, and a nitrogen base. There are four different nitrogen bases: adenine (A), thymine (T), guanine (G), and cytosine (C). A always pairs with T, and G always pairs with C.
Answer: the two tropics zones
Explanation:
Between the two tropics zones, which includes the equator, the Sun is directly overhead twice per year. Outside the tropic zones, whether to the south or north, the Sun is never directly overhead. Two other significant lines of latitude are the Arctic Circle (around the North Pole) and the Antarctic Circle (around the South Pole).
Answer:
It is true to say that by using cuttings, exact genetic characteristics can be maintained, because the cuttings retain the same genetic information about the plant from which they were extracted.
Explanation:
Cuttings are buds or branches extracted from a plant to obtain a plant of the same species, through a type of asexual reproduction.
Once separated from the "progenitor" plant, the cutting is provided with a suitable medium for growth, and will have the possibility of growing roots, developing and growing as an independent plant, with the same genetic characteristics of the original plant, as if it were a clone.
In this reproductive process, man intervenes.
