Which vitamin is essential for the absorption of calcium from the intestine?
A. Vitamin B₁
B. Vitamin C
C. Vitamin D
D. Vitamin A
Answer: Option C
Solution (By JKExamLibrary)
Vitamin D (calciferol) promotes the absorption of calcium and phosphorus from the small intestine by inducing synthesis of calcium-binding proteins. It is synthesized in the skin upon exposure to UV light and then activated in the liver and kidneys. Deficiency leads to rickets in children and osteomalacia in adults. Vitamin A is for vision, C for collagen, B₁ for energy metabolism.
Explanation:
The joints between skull bones are immovable fibrous joints called sutures, where bones are tightly connected by dense connective tissue. Hinge joint (elbow, knee) allows movement in one plane. Ball and socket (shoulder, hip) allows multi-directional movement. Pivot joint (atlas-axis) allows rotational movement. Sutures fuse completely in old age.
Explanation:
Fucoxanthin is a carotenoid that masks the green chlorophyll in brown algae (Phaeophyceae). Phycoerythrin is red, phycocyanin blue, chlorophyll b green.
Explanation:
In botanical classification, the term 'Division' corresponds to 'Phylum' in zoological classification. For example, flowering plants are in the Division Magnoliophyta (or Angiosperms), while animals are in Phyla like Chordata. The hierarchy is Kingdom → Division/Phylum → Class → Order → Family → Genus → Species. This terminological difference is a key point in taxonomy.
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