The correct answer is option A
A person that is having an allergy with pollen grains should take antihistamines.
When there is an allergic reaction in the body then the body releases histamines which evokes immune response.
As a result of this the person starts sneezing, runny nose, hives et cetera.
So, one should take antihistamines to prevent the action of histamines on the body.
These genes could have arisen by gene duplication.
<h3>What is gene duplication?</h3>
Gene duplication is the process of copying a section of DNA that codes for a gene. A retro transposition event or a recombination mistake are both potential causes of gene duplication. As a result, the duplicate gene coding may experience a significant number of modifications throughout time. This might prevent the gene from functioning or, in other situations, give the creature a benefit.
Gene duplication is a phenomenon that can happen through a variety of ways:
- Ectopic Recombination: Uneven crossing-over between misaligned homologous chromosomes during meiosis might result in duplications. A duplication at the exchange site and a reciprocal deletion are the results of this recombination.
- Replication Slippage: Short genomic sequences can be duplicated as a result of the replication error known as replication slippage. DNA polymerase starts copying the DNA during replication, but eventually the polymerase separates from the DNA, causing replication to stall. The replicating strand is incorrectly aligned when the polymerase reattaches to the DNA strand, which accidentally results in several copies of the same portion.
- Aneuploidy: When a single chromosome's nondisjunction causes an abnormally high number of chromosomes, this condition is known as aneuploidy. Aneuploidy is frequently damaging and frequently causes spontaneous miscarriages in mammals. Some aneuploid people can survive. For instance, human trisomy 21 causes Down syndrome but is not lethal.
Learn more about gene duplication here:
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Answer:
500-million-year-old fossil found in BC is ancient ancestor of spiders and scorpions. Palaeontologists in British Columbia have found a fossil of the oldest known ancestor of scorpions and spiders.
Amino acids form ionic bonds called 'hydrogen bonds' with hydrogens attachjed to other amino acids. This happens to hold your DNA double helix together :)
