66.Given below are two statements, labeled as Assertion (A) and Reason (R). In the context of the two statements, which of the following is correct ?Assertion (A) : Plaster of Paris is used by doctors for setting fractured bones.Reason (R) : When Plaster of Paris is mixed with water and applied around the fractured limbs, it sets into a hard mass.

67.Given below are two statements, labeled as Assertion (A) and Reason (R). In the context of the two statements, which of the following is correct ?Assertion (A) : Leakages in household gas cylinders can be detected.Reason ® : LPG contains ethyl merceptan which is a smelling agent.

68.Of the following, which one is the best insulator ?

69.Given below are two statements, labelled as Assertion (A) and Reason (R). In the context of the two statements, which of the following is correct ?Assertion (A) : All flying animals belong to the clas of Aves.Reason (R) : All flying animals have wings.

70.Given below are two statements, labeled as Assertion (A) and Reason (R). In the context of the two statements, which of the following is correct ?Assertion (A) : Radio carbon dating is a precise method of determining the age of ancient objects.Both A and R are true but R is the correct explanation of A.Reason (R) : Once an object dies, teh amount of radioactive carbon present in it decreases with time following a definite law.