The extra X chromosome is received from mother.
<h3><u>Explanation</u>:</h3>
Klinefelter's syndrome is the condition of chromosomal aberration where the person has an extra X chromosome. This means the genotype of the person is 44+XXY and the total chromosome number is 47. This condition is achieved due to inappropriate meiotic division and one of the sperm or ovum has the an extra X chromosome.
Here both the parents are normal in terms of colour vision. So the father cannot have the gene of colour blindness because if it was present, then father would have been colour blind because he has only one X chromosome per cell. So its present in mother who is heterozygous in terms of colour blind gene. So the extra X chromosome also came from her which made the presence of two defective X chromosomes in the offspring and made it colour blind.
The best answer to the question 'What are the nonliving components of the environment that shape an ecosystem?' would be letter d. Abiotic factors are those components of the environment that are non-living or does not have life. All the other choices have life.
Answer:
The post-transcriptional modifications in the mRNA produced as a result of the transcription in eukaryotes provide many advantages to the mRNA.
The two post-transcriptional modifications are the addition of 7-methylguanosine cap at 5' end of mRNA called capping whereas the addition of the poly(Adenyl) tail at 3' end called tailing.
The advantages of capping are:
1. Protection of nascent mRNA from the degradation.
2. Recognition by transcription factors helps in translation.
The advantages of tailing are:
1. Protection of the mRNA from enzymatic degradation in the cytosol.
2. Transcription termination
3. Export of the mRNA from the nucleus
<h2><u>Answer:</u></h2>
Fossil: is preserved pre historic life form present under ground at high pressure for a long time.Animal die and burried under layers of sediments.
It provides evidence about the history of life on earth. It also shows different groups of organisms, including species,that have changed over time. Because the formation of any fossil depends upon the precise combination of conditions.
As the world changes, plants and animals change with time . From fossils we compare organisms of modern time with ancient , the species we see today are very different from species that lived in the past. Thus, the fossil record can be used to show that organisms changed to meet new condition.
