Identify the correct statement about plant diseases: MCQ with Answer and Explanation

Identify the correct statement about plant diseases:
A. Late blight of potato is caused by a bacterium.
B. Tobacco mosaic disease is caused by a virus.
C. Black rust of wheat is caused by a bacterium.
D. Citrus canker is caused by a virus.
Answer: Option B
Solution (By JKSSB Mock Tests)
Tobacco mosaic is viral. Citrus canker is bacterial, late blight is an oomycete (fungus-like), black rust is fungal.

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Practice More Biology Questions

Question #1
The plant cell wall is primarily composed of which of the following?
A. Silica and Calcium
B. Proteins and Lipids
C. Cellulose, Hemicellulose, and Pectin
D. Chitin and Peptidoglycan

Correct Answer: Option C


Explanation:
The plant cell wall is primarily made up of cellulose, hemicellulose, pectins, and proteins. Cellulose provides the main structural framework, while hemicellulose and pectins help in cross-linking and providing flexibility. Chitin is found in fungal cell walls, and peptidoglycan is found in bacterial cell walls.

This question belongs to: Science Biology
Question #2
Which part of the nephron is primarily involved in the reabsorption of glucose and amino acids?
A. Collecting duct
B. Proximal convoluted tubule
C. Loop of Henle
D. Distal convoluted tubule

Correct Answer: Option B


Explanation:
The proximal convoluted tubule (PCT) reabsorbs about 70-80% of electrolytes and water, and almost 100% of glucose, amino acids, and vitamins back into the blood via active transport and facilitated diffusion. The loop of Henle concentrates urine, the DCT reabsorbs sodium and water under hormonal control, and the collecting duct reabsorbs water (ADH-dependent). PCT cells have microvilli for increased surface area.

This question belongs to: Science Biology
Question #3
The fluid that lubricates joints and reduces friction is:
A. Aqueous humor
B. Pleural fluid
C. Cerebrospinal fluid
D. Synovial fluid

Correct Answer: Option D


Explanation:
Synovial fluid is a viscous, egg-white-like fluid secreted by the synovial membrane in synovial joints (e.g., knee, hip). It lubricates articular cartilage, reducing friction and wear, and also nourishes cartilage. CSF cushions CNS, pleural fluid reduces lung friction, aqueous humor is in the eye.

This question belongs to: Science Biology