Q11. Which of the following is a characteristic feature of lichens?
a) They are parasitic
b) They have roots for absorption
c) They are indicators of pollution
d) They require sunlight for growth
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Correct Answer: c) They are indicators of pollution
Explanation: Lichens are sensitive to air pollution and are often used as bioindicators of environmental health.
Q12. The genetic material of viroids is composed of:
a) Double-stranded DNA
b) Single-stranded DNA
c) Double-stranded RNA
d) Single-stranded RNA
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Correct Answer: d) Single-stranded RNA
Explanation: Viroids are composed of single-stranded RNA molecules.
Q13. Which of the following is NOT a method to control viral diseases?
a) Vaccination
b) Antibiotics
c) Quarantine
d) Antiviral drugs
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Correct Answer: b) Antibiotics
Explanation: Antibiotics are ineffective against viral infections as they target bacteria, not viruses.
Q14. Lichens are capable of surviving in extreme environments due to:
a) Their ability to photosynthesize
b) Their symbiotic relationship
c) Their resistance to radiation
d) Their ability to form spores
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Correct Answer: b) Their symbiotic relationship
Explanation: The symbiotic relationship between the fungal and algal components of lichens helps them withstand harsh environmental conditions.
Q15. The shape of a virus is determined by the arrangement of its:
a) Capsid proteins
b) Lipid membrane
c) Nucleic acids
d) Enzymes
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Correct Answer: a) Capsid proteins
Explanation: The shape of a virus is determined by the arrangement of its capsid proteins.
Q16. Which of the following diseases is caused by a viroid?
a) Ebola
b) HIV/AIDS
c) Potato spindle tuber disease
d) Tuberculosis
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Correct Answer: c) Potato spindle tuber disease
Explanation: Potato spindle tuber disease is caused by a viroid called Potato spindle tuber viroid (PSTVd).
Q17. Lichens contribute to ecosystem health by:
a) Decomposing organic matter
b) Fixing atmospheric nitrogen
c) Providing food for insects
d) Producing antibiotics
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Correct Answer: b) Fixing atmospheric nitrogen
Explanation: Lichens play a crucial role in nitrogen fixation, converting atmospheric nitrogen into a form usable by plants.
Q18. The protein coat of a virus is also known as a:
a) Capsid
b) Nucleocapsid
c) Envelope
d) Sheath
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Correct Answer: a) Capsid
Explanation: The protein coat of a virus is called a capsid, which encloses the genetic material.
Q19. Which of the following is a viral disease transmitted by mosquitoes?
a) Dengue fever
b) Tuberculosis
c) Malaria
d) Cholera
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Correct Answer: a) Dengue fever
Explanation: Dengue fever is a viral disease transmitted by Aedes mosquitoes.
Q20. Viroids were first discovered to cause diseases in:
a) Plants
b) Animals
c) Humans
d) Fungi
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Correct Answer: a) Plants
Explanation: Viroids were first discovered as the causative agents of diseases in plants.