Answer:
A and B is correct.
Explanation:
Mutations are spontaneous variations to nucleotide sequences, therefore in two animals or two chromosomes they can not be identical by nature. Therefore, the introns interact with non-coding sequences and therefore their sequences are not established as consensus in nature and are therefore highly prone to mutations.
Hence both the statement are correct.
Answer:
The chance of a normal couple having a child with down syndrome is 1 to 600 births.
Explanation:
Down syndrome is a genetic flaw that occurs when the fetus is being formed.
A human cell considered normal has 46 chromosomes, divided into 23 pairs. For some unknown reason, an error may occur at the beginning of embryonic development and an extra chromosome is created, which binds to par 21. The result is cells with 47 chromosomes. This causes the said syndrome.
It is important to know that this failure happens at random. It is nobody's responsibility. It has not been proven to date that lifestyle, actions during pregnancy, smoking, drinking, medicines, environmental factors or kinship between the couple can influence this occurrence. She is not contagious either. The likelihood of a normal couple having a child with the syndrome is approximately 1 to 600 births.
Answer:
8 chromosomes in each daughter cell
Explanation:
Mitosis creates identical cells. If there are 8 chromosomes in the parent cell, there will be 8 chromosomes in each daughter cell. The way it works is that in late Interphase, the number of chromosomes and DNA double. In this case there would be 16 chromosomes. And when the cell splits into two during cytokinesis, each of the two would get half the chromosomes. Hence, there would be 8 chromosomes in each daughter cell.
