Aziz has Down syndrome.
Down syndrome or trisomy 21 is a genetic disorder which results in physical growth delays and mild / moderate intellectual disability. Patients with this disorder have characteristic facial features and their IQ is usually equivalent to the mental ability of an 8 or 9-year-old child.
 
        
             
        
        
        
Answer:
(1) Nitrite poisoning 
(2)  Its cause is elevated levels of nitrite in the pond or culture system water. 
 
        
             
        
        
        
Explanation:
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Answer:
50000
Explanation:
number of paramecium in 1 gallon of water = 50
number of paramecium in 1000 gallons of water = 
1000× 50 = 50000