Answer:
The answer should be C
Explanation:
If you look at the the graph, C points to the time period after mammals appeared. Since birds are mammals, they should have appeared after the time that mammals first came to be on Earth.
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Answer:
Option-D
Explanation:
In the given question the genotype of parental allele is- AbaB X AbaB. The alleles formed will be- AB, Ab,aB, ab in which the crossover allele will be AB and ab.
1. Unlinked genes
Now of these alleles are unlinked then the alleles will assort independently of each other therefore performing the punnett square we will get dihybrid ratio as 9:3:3:1 in which
1. A_B_ are 9
2. aaB_ are 3
3. A_bb are-3
4. aabb- 1
Since the crossover allele are AB and ab therefore A_B_ are 9 and aabb- 1 represent recombinant genotype.
2. Linked genes
When the genes will be linked then chances of crossing over will be reduced as a result of which only two type of allele will be formed which are- Ab and aB and the recombinant frequency will become less.
Crossing these allele will form Aabb
, AaBb
, AaBb and aaBB genotypes.
The recombinant ratio will decrease as A_B_ is 2 and aabb is not present.
Thus, option-4 which states that the unlinked ration is 9:3:3:1 and linked ratio is <9: >3: >3: <1 is correct.
DNA is a nucleic acid molecule that undergoes a replication process to form a new daughter strand. The blue segment is the parental strand, and the yellow is the daughter strand.
<h3>What is replication?</h3>
Replication is the process of the central dogma that duplicates the copy of the parent strand into new daughter strands. The two helixes of the parent strand get separated to make the complimentary copy of the new strand.
The daughter DNA is semi-conservative and are complementary structure made from the duplication of the parent strand with the help of the replication enzymes.
Therefore, the daughter strands are the semi-conservative copies of the parental strand.
Learn more about replication here:
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