The fungi constitute a unique kingdom of heterotrophic organisms. They show a great diversity in morphology and habitat. You must have seen fungi on a moist bread and rotten fruits. The common mushroom you eat and toadstools also belong to fungi. White spots seen on mustard leaves are due to a parasitic fungus. Some unicellular fungi, e.g., yeast are used to make bread and beer. Other fungi cause diseases in plants and animals; wheat rust-causing Puccinia is an important example. Some are the source of antibiotics, e.g., Penicillium. Fungi are cosmopolitan and occur in air, water, soil and on animals and plants. They prefer to grow in warm and humid places. Have you ever wondered why we keep food in the refrigerator? Yes, it is to prevent food from going bad due to bacterial or fungal infections.
Assertion (A): Parasitic fungi can cause visible symptoms on their host plants. Reason (R): White spots seen on mustard leaves are due to parasitic fungal infections.
Correct answer: A — If both assertion and reason are true and the reason is the correct explanation of the assertion.
Both statements are true from NCERT. Parasitic fungi do cause visible symptoms (Assertion true). NCERT states “White spots seen on mustard leaves are due to a parasitic fungus” (Reason true). The Reason provides a specific example that explains HOW the visible symptoms mentioned in the Assertion are caused by parasitic fungal infections.
MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.