21.Liquid is characterised by

22.Consider the following statements : A. Pure germanium is doped with pentavalent metals like antimony and phosphorus to make it n-type semiconductor. B. Pure germanium is doped with trivalent metals like gallium and indium to make it p-type semiconductor.

23.Which of the following is used as an insecticide ?

24.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 ? 1. Assertion (A) : Blood group O is a universal donor. 2. Reason (R) : Blood type O has both antigen A and B.

25.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) : Birds do not lay eggs by millions as some of teh lower animals do.Reason (R) : Survival rate is much higher because of the parental care.