(a) The deficiency of vitamin D and lack of calcium in any child's diet causes rickets. As both vitamin D and calcium is important for healthy bones.
(b) Example of fibrous protein is $\mathit{\alpha }$-keratin. Hairs, nails and collagens majorly contains this protein.
Example of globular protein is haemoglobin; it plays the main role in carrying oxygen in the blood.
(c) Gluconic acid $\left({\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_7\right)$
On reacting glucose with bromine water, glucose undergoes oxidation reaction to form gluconic acid as a product.