Consider statements about scientists: 1. Robert Hooke discovered the cell. 2. Louis Pasteur disproved spontaneous generation. 3. Alexander Fleming discovered the structure of DNA. Which are correct? MCQ with Answer and Explanation
Consider statements about scientists: 1. Robert Hooke discovered the cell. 2. Louis Pasteur disproved spontaneous generation. 3. Alexander Fleming discovered the structure of DNA. Which are correct?
A. 1, 2 and 3
B. 1 and 3 only
C. 2 and 3 only
D. 1 and 2 only
Answer: Option D
Solution (By JKSSB Mock Tests)
Robert Hooke first observed and coined the term 'cell' in 1665 using cork tissue. Louis Pasteur definitively disproved the theory of spontaneous generation using his swan-neck flask experiment. Alexander Fleming discovered the antibiotic penicillin, not the structure of DNA; that was elucidated by Watson and Crick. Thus, statements 1 and 2 are correct.
Explanation:
Cuscuta (dodder) is a parasitic plant that lacks chlorophyll and derives nutrients from the host plant through haustoria. It is a total stem parasite. Mango, neem, and sunflower are autotrophic plants performing photosynthesis. Heterotrophic plants include parasites (Cuscuta, Rafflesia) and saprophytes (Monotropa).
Explanation:
Azolla is an aquatic fern that harbors the nitrogen-fixing cyanobacterium Anabaena azollae in its leaf cavities. It is extensively used as a biofertilizer in rice paddies, adding organic nitrogen. Rhizobium fixes nitrogen in legume roots, Azotobacter is free-living in soil, mycorrhiza is a fungal association enhancing phosphorus uptake. Azolla multiplies rapidly and improves soil fertility.
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