Answer:
<em>Exceptions to Mendel's principles:
</em>
Does exceptions mean that Mendel was "wrong"? The answer is "NO". It means that we know more today about diseases, genes, and heredity than compared to what he expalined 150 years ago. Here I have summerized the exceptions with examples:
<em>Incomplete dominance</em>: When an organism is heterozygous for a trait and both genes are expressed but not completely.
<em>Example</em><em>:</em> SnapDragon Flowers
<em>Codominance</em>: When 2 different alleles are present and both alleles are expressed.
<em>Example</em>: Black Feathers + Whites feathers --> Black and white speckled feathers
<em>Multiple alleles</em>: Three or more alternative forms of a gene (alleles) that can occupy the same locus.
Example: Bloodtype
<em>Polygenic traits</em>: more than one gene controls a particular phenotype
Example: human height, Hair color, weight, and eye, hair and skin color.
<span>The best method used to prevent soil depletion would be contour farming.
In contour farming, the land is tiled in consistent elevation. Contour farming is efficient in reducing soil depletion because it can conserve rain water and reduce the erosion of soil.
If there is no contour farming in your option, then choose A. Adding fertilizer. </span>
Explanation:
1) The enzyme helicase catalyses the unwinding of the two DNA strands by disrupting the hydrogen bonds between complementary base pairs.
2) Single-stranded binding proteins attach to the DNA strands to stabilise them and prevent them from joining back together.
3) The enzyme primase catalyses the addition of a short primer consisting of RNA nulceotides to the DNA strand. This serves as an 'anchor' DNA polymerase to initiate replication.
4) The enzyme DNA polymerase synthesizes a new DNA strand by incorporating DNA nucleotides complementary to the existing strand. DNA polymerase activity only occurs in the 5' ---> 3' direction.
5) The enzyme ligase catalyses the formation of hydrogen bonds between the two new pairs of DNA strands, and seals any breakages in the sugar-phosphate backbone.
<span>i think Comparative morphology
i could be wrong tho</span>
Answer: The following is a <u>postzygotic isolating barrier </u>:
- The hybrid offspring of two species of crocodiles can produce normal gametes but cannot obtain a mate.
Explanation:
<em><u>Reproductive isolation </u></em>occurs when <em>barriers prevent</em> two populations from interbreeding , <u>keeping their gene pools separate.</u>
We can find the Prezygotic isolation that occurs<u> before fertilization </u>can happen.
And the Postzygotic insolation barriers are the reproductive insulation processes that<u> act after the mating</u>. They are all that concern the viability of the individuals produced.
Prezygotic isolation barriers can be temporal, behavioural, geographic , ecological or mechanical; whereas postzygotic isolation barriers include the inviability, infertility or breakdown of hybrid organisms
