Answer:
hope this helps
Explanation:
About 95 percent of the time, Down syndrome is caused by trisomy 21 — the person has three copies of chromosome 21, instead of the usual two copies, in all cells. This is caused by abnormal cell division during the development of the sperm cell or the egg cell.
 
        
             
        
        
        
Answer:
true 
Explanation:
I hope it helps 
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Answer -
T-Cell - White blood cell = Fight off Intruders in the body
B-Cell - Macrophages = Creates Antibodies against antigen.
Cell Differentiate - Stem Cells = My favorite cell of all time in animal because they can turn into almost any cell like neural, signaling, euthyroid. Etc
        
             
        
        
        
I believe they are carbohydrates
        
             
        
        
        
The major histocompatibility complex (MHC<span>) is a set of cell surface proteins essential for the acquired immune system to recognize foreign molecules in vertebrates, which in turn determines histocompatibility. ... The human </span>MHC<span> is also called the </span>HLA<span> (human leukocyte antigen) complex (often just the </span>HLA<span>).</span>