46.Who among the following received Nobel Prize twice for the same subject ?

47.For the production of good sound, the flute should be made of

48.The colour of an opaque object is due to the colour it

49.Study of life in outer space is

50.Which of the following conclusions have been deduced from the study of fossils ? 1. Many species that existed in the past are now extinct. 2. Complex species have evolved from pre-existing simple forms. 3. Living organisms have the capacity reproduce. 4. Living organisms depend on meterials available on the earth for all their requirements.