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PCR is a useful technique because it is used to amplify small segments of DNA.
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Soil
Soil is the upper layer of the ground comprising of a mixture of sand, silt, clay, loose rock fragments, and organic matter that can support the growth of rooted plants. The relative proportions of sand, silt and clay determine the texture and size of the pores of the soil, which affects its ability to allow air and water to penetrate/infiltrate.
Answer:
A malaria outbreak causing allele frequencies to change is an example of <u><em>natural selection.</em></u>
Explanation:
Natural selection is a type of selection in which those organisms are favoured to live and reproduce which are better adapted to live in an environment. Due to natural selection, the allele frequencies of a population will tend to change with the passage of time.
When the outbreak of malaria occurs, those organisms which do not catch malaria are able to survive and pass on their characteristics to their offsprings. the other organisms die and do not reproduce. This will cause changes in the allele frequencies.
Answer:
3/16
Explanation:
<u>According to Mendel's law of independent assortment of genes, when a dihybrid cross involves two genes that assort independently and one of the parents is dominant for the two genes and the other is recessive, the phenotypic ratio of the offspring at F2 would be 9:3:3:1</u>. The proportion of the offspring with the dominant parental traits would be 9/16, those with the recessive parental traits would be 1/16, while those with mixed traits would be 3/16 each.
Assuming the eye color is represented by E and the wing shape is represented by W. At F2
EeWw x EeWw
E_W_ - 9/16 (dominant for both eye color and wing shape)
E_ww - 3/16 (dominant for eye color and recessive for wing shape)
eeW_ - 3/16 (recessive for eye color and dominant for wing shape)
eeww - 1/16 (recessive for both eye color and wing shape)
<em>Hence, the proportion of the offspring with dominant phenotype for eye color and recessive phenotype for wing shape would be </em><em>3/16.</em>
Answer: <u>Option 4; Oxygen gains electrons and hydrogen to form water.
</u>
Respiration is a process where glucose is used and energy is released stored in this molecule. Oxygen is used during respiration as well and it gains the electrons and hydrogen to form water. And, gain of electrons is an oxidation reaction. So answer is option 4.
Since, oxygen is consumed during respiration, option 1 is incorrect.
Loss of electrons is reduction, so option 2 is also incorrect.
Glucose is used in respiration, thus option 3 is incorrect.