1) With reference to ‘stem cells’, frequently in the news which of the following statements is/are correct?
1. Stem cells can be derived from mammals only.
2. Stem cells can be used for screening new drugs.
3. Stem cells can be used for medical therapies.
Select the correct answer using the codes given below:
(A) 1 and 2
(B) 2 and 3 only
(C) 3 only
(D) 1, 2 and 3

2) A team of scientists at Brookhaven National Laboratory including from India created the heaviest anti-matter (anti-helium nucleus). What is/are the implications of the creation of anti-matter?
1. It will make mineral prospecting and oil exploration easier and cheaper.
2. It will help probe the possibility of the existence of stars and galaxies made of anti matter.
3. It will help understand the evolution of the universe.

Select the correct answer using the codes given below:
(A) 1 only 
(B) 2 and 3 only
(C) 3 only
(D) 1, 2 and 3

3) Recently there has been a concern over the short supply of a group of elements called rare earth metals. Why?
1. China, which is the largest producer of these elements, has imposed some restrictions on their export.
2 Other than china, Australia, Canada, Chile, these elements are not found in any country.
3 Rare earth metals are essential for the manufacture of various kinds of electronic items and there is growing demand for these elements.

Select the correct answer using the codes given below:
(A) 1 only
(B) 2 and 3 only
(C) 1 and 3 only
(D) 1, 2 and 3

4) Graphene is frequently in news recently. What is its important?
1. It is a two-dimensional material and has good electrical conductivity.
2. It is one of the thinnest but strongest materials tested so far.
3. It is entirely made of silicon and has high optical transparency.
4. It can be used as ‘conducting electrodes’ requires for touch screens, LCD’s and organic LED’s

Which of the statements given above are correct?
(A) 1 and 2 only
(B) 3 and 4 only
(C) 1,2 and 4  only
(D) 1, 2, 3 and 4