(a) List important difference between tendons and ligaments.
(b) Which protein forms dense, hard matrix of bone ?
(c ) What is meant by decalcified bone ?
(d) Name two long bones present in human body. These bones have a cavity in the centre. What is it called ?

Explanation

(b) Ossein.
(c ) If a bone is kept in a dilute acid (5% nitric acid ) for sometime, its inorganic part is dissolved and organic part is left behind. Such a bone is said to be decacified bone.
(d) Humerus and femur bones are long bones. These have marrow cavity in the centre.