The term 'ecology' was coined by: MCQ with Answer and Explanation

Explanation:
Vitamin B₁₂ contains a cobalt ion at the center of its corrin ring structure, hence the name cobalamin. It is essential for DNA synthesis and nervous system function. Iron is in heme, magnesium in chlorophyll, zinc in many enzymes. B₁₂ is unique in having a metal-carbon bond.

Explanation:
Fossils are the preserved remains or traces of ancient organisms, providing crucial evidence for evolution. Analogous organs (like wings of birds and insects) perform similar functions but have different structural plans and evolutionary origins, indicating convergent evolution. Jean-Baptiste Lamarck proposed the theory of inheritance of acquired characters, while Charles Darwin proposed natural selection. Thus, statements 1 and 2 are correct.

Explanation:
Azotobacter is a free-living, aerobic, nitrogen-fixing soil bacterium used as a biofertilizer for non-legume crops like wheat, maize, and cotton. Rhizobium is symbiotic, Nostoc is a cyanobacterium (algal biofertilizer), and mycorrhiza is a fungal symbiont that enhances phosphorus uptake. Biofertilizers reduce the need for chemical nitrogen fertilizers and are eco-friendly.