Answer:
The presence of an additional chromosome
Explanation:
Look at "pair" 21. See how there are THREE chromosomes instead of TWO? Normally, there would only be two chromosomes in each pair but this karyotype shows a trisomy (see def. below) of the 21st pair. This was caused by a nondisjunction mutation of the 21st pair. The is also the karyotype of a person with Down's Syndrome.
Definition of Trisomy:
A condition of the presence of three chromosomes in a pair instead of two. This normally causes developmental irregularity.
Read the question fully.
Think about a severe weather situation you have experienced near your home or have witnessed on the news.
The question is asking you to tell about any severe weather that you have seen, heard, or you've experienced about and just tell them about it.
The answer will be B. It is common sense
Im pretty certain it is volcanic eruption
