The correct asnwer to your question - why would a group of antelopes leave the herd for search of a better grassland is an example of emigration - B.
These antelopes would emigrate to a certain grassland and be immigrants in that grassland. This has to be distinguished.
Down syndrome and Alzheimer's disease.
Down syndrome is a chromosomal disorder which is caused by the presence of extra copy of chromosome 21. Therefore also called as Trisomy 21.
Alzheimer's disease is a most common form of dementia(reduction in brain functioning). It is caused by mutation in single gene APP (Amyloid Precursor Protein) present on chromosomer 21.
It’s all of them because they all end in autotrophs
