Distillation is one of the processes that are used in the laboratory to remove impurities from substances. Distillation employs the differences in the boiling points of two liquids to separate them. The distillation apparatus must have an opening to the atmosphere at an end in order to avoid developing a dangerously high pressure within the system when heat is applied.<span />
What phenotypic ratio would you expect as a result of a test cross between a dihybrid organism and one that is homozygous recessive for alleles at two independent loci?
a. 3:1
b. 9:3:3:1
c. 1:1:1:1
d. 1:2:1
e. 9:4:2:1
Answer:
c. 1:1:1:1
Explanation:
When a heterozygous individual for two genes is test crossed with a double homozygous recessive individual, the progeny is obtained in 1:1:1:1 phenotypic ratio. This occurs as the heterozygous dominant individual forms four types of gametes in 1:1:1:1 ratio while the homozygous recessive individual would form only one type of gamete having one recessive allele for each gene.
For example, a test cross between TtRr (tall and red) and ttrr (short and white) would produce a progeny in following ratio=
1 tall, red: 1 tall, white: 1 short, red: 1 short, white
Here, T= tall, t= short, R= red, r= white
<span>There are so many societal issue that scientists will be able to address using the sequence of the human genome. For example, health epidemics. Using the genome, scientists can easily found how a pathogen affects a population and search for genes that can inhibit the pathogen. But no all health epidemics are caused by a pathogen. The obesity, nowadays a social health issue in so many countries, is an epidemic that can be address using the human genome. Also, the drug Abuse and Addiction. Scientific have found genes that are related to obesity and also genes related to drug addition. A person who have these genes is more likely to suffer those conditions. But, the discover of these genes and the disease relation help scientists to search for a better treatment.</span>
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Metamorphic rocks are created by the physical or chemical alteration by heat and pressure of an existing igneous or sedimentary material into a denser form.
