CBSE biology
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According to de-Vries what is saltation?
According to De Vries, Saltation is a single step large mutation which leads to speciation.
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Excessive nutrients in a fresh water body cause fish mortality. Give two reasons
The presence of large amounts of nutrients in the water bodies lead to excessive growth of algae and cause Algal bloom. The algal blood leads to deterioration of the quality of water, reduces dissolved oxygen and the hence leads to fish mortality.
Suggest the breeding method most suitable for animals that are below average in milk productivity.
The breeding method of Out-crossing is Most suitable for animals that are below average in milk productivity. In this method, the animal of the same breed but having no common ancestors on either side of their pedigree for up to 4-6 generations are mated.
State a difference between gene and an allele.
| Gene | Allele |
| Gene is a unit of inheritance that is transferred from the parent to the offspring. | Allele is the alternative form of a single gene that lie on the same locus in the homologous chromosomes. |
Sugggest a technique to a researcher who needs to separate fragments of DNA.
The researcher can use the method Electrophoresis (Gel electrophoresis to separate the fragments of the DNA. In this method, the DNA fragments are loaded into the well made in the gel and separated according to their size under the influence of an electric current.
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Mock Test Series
Mock Test Series