In old age, the vision of eye becomes dim. It is due to

In old age, immune system becomes weak due to gradually degeneration of :

Due to presence of __________ in the eye of Pigeon, the vision becomes very sharp .(Fill in the blank and write the complete sentence)

Immune response of old age person becomes weak due to the degeneratio of following gland

Immune response of old age person becomes weak due to the degeneratio of following gland

In old age, stiffness of joints is due to the

In old age, stiffness of joints is due to the

In old age, stiffness of joints is due to the

In old age, stiffness of joints is due to the