The disease caused by the bacterium Vibrio cholerae is characterized by:
A. Severe watery diarrhea (rice-water stools)
B. Persistent cough
C. High fever and rash
D. Bloody diarrhea
Answer: Option A
Solution (By JKExamLibrary)
Cholera, caused by Vibrio cholerae, produces cholera toxin that stimulates massive secretion of water and electrolytes into the intestinal lumen, leading to profuse, watery diarrhea resembling rice water, causing rapid dehydration. Treatment is oral rehydration therapy and antibiotics. Typhoid causes fever, dysentery causes bloody stools.
Explanation:
Color blindness (specifically red-green color blindness) is an X-linked recessive disorder. The gene responsible is located on the X chromosome. Males (XY) are more frequently affected because they only have one X chromosome; a single recessive allele will cause the disorder. Females (XX) need two recessive alleles to be affected, making them more likely to be carriers.
Explanation:
Sclerenchyma cells have thick, lignified secondary walls and are often dead at maturity, providing rigid structural support. Fibers and sclereids are examples. Parenchyma is living and thin-walled, collenchyma living with uneven thickening, aerenchyma has air spaces.
Explanation:
Nitrogen is an essential component of amino acids (proteins) and nitrogenous bases of nucleic acids (DNA, RNA). Phosphorus is in nucleic acids and ATP, potassium is an ion, calcium is structural. The nitrogen cycle makes atmospheric Nā available to organisms through fixation.
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