Which of the following is a correct statement about biofertilizers?
A. They are living organisms that enrich soil nutrient content.
B. They are synthetic growth regulators.
C. They are toxic to soil organisms.
D. They are chemical fertilizers that enhance crop yield.
Answer: Option A
Solution (By JKSSB Mock Tests)
Biofertilizers contain living microorganisms like bacteria, cyanobacteria, and fungi that increase nutrient availability (e.g., nitrogen fixation, phosphorus solubilization) for plants. They are eco-friendly and sustainable. Chemical fertilizers are synthetic inorganic salts. Biopesticides control pests. Examples: Rhizobium, Azotobacter, mycorrhiza. Biofertilizers improve soil health without chemical residue.
Explanation:
The anther is the terminal part of the stamen (male reproductive organ) where pollen grains are produced through microsporogenesis. Stigma is the receptive surface for pollen, style connects stigma to ovary. Ovary contains ovules, which develop into seeds after fertilization. The anther has four microsporangia (pollen sacs).
Explanation:
Crossing over occurs during prophase I of meiosis, not in mitosis. Mitosis produces identical diploid cells, meiosis reduces chromosome number by half, and cytokinesis divides the cytoplasm.
Explanation:
Broilers are chickens bred and raised specifically for meat, reaching market weight in 6-8 weeks. Layers are hens raised for egg production. Broilers require high-protein diet and management to maximize growth. Poultry farming is an important sector for protein supply. Some breeds like Rhode Island Red are dual-purpose. Cobb and Ross are popular broiler strains.
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