The vitamin that is required for the absorption of calcium from the gut is: MCQ with Answer and Explanation

Explanation:
The tracheal wall contains C-shaped hyaline cartilage rings that keep the airway open, preventing collapse due to negative pressure during inspiration. Smooth muscle and fibrous tissue connect the rings, ciliated epithelium sweeps mucus upward.

Explanation:
Decomposition involves several steps. Leaching is the process where water-soluble inorganic nutrients (like nitrates, phosphates) are washed out of the decomposing organic matter (detritus) and move deep into the soil profile, where they may become unavailable to plants. Fragmentation is the breakdown of detritus by detritivores (like earthworms).

Explanation:
Sedimentary rocks, such as limestone, shale, and sandstone, form in layers from accumulated sediments and preserve remains of organisms as fossils. Igneous rocks from volcanic activity and metamorphic rocks formed under high temperature/pressure rarely contain fossils. The fossil record provides evidence for evolution, showing gradual changes in species over geological time. Fossils include bones, shells, imprints, and amber inclusions.