636: The given pie charts show the proportion of literates and illiterates in a country, in the year 1970 and 1990 and also the proportion of males (M) and females (F) among the literates. Which one of the following statements can be said to be beyond any doubt ?
(a) In 1970 has of the illiterates were women (females)
(b) The proportion of literate males to the total population of males remained the same over the years
(c) Male literacy did not improve over this period
(d) The ratio of female literates to male literates improved significantly over this period
637: The working principle of a washing machine is
(a) centrifugation
(b) dialysis
(c) reverse osmosis
(d) diffusion
638: With reference to the latest developments in stem cell research, consider the following statements:
1. The only source of human stem cells are the embryos at blastocyst stage
2. The stem cells can be derived a without causing destruction to blastocysts
3. The stem cells can regenerate themselves in vitro virtually forever
4. Indian research centres also created a few cell lines which can be developed into many types of tissues
Which of these statements are correct?
(a) 1, 2, 3 and 4
(b) 1, 2 and 3
(c) 1, 2 and 4
(d) 3 and 4
639: The surface area of a cube is 216 sq.m. What is its volume ?
(a) 100 cu m
(b) 216 cu m
(c) 480 cu m
(d) 512 cu m
640: Rickets is caused due to:
(a) Deficiency of Vitamin A
(b) Deficiency of Vitamin D
(c) Deficiency of Vitamin C
(d) Low intake of proteins