1821: The best quality of hard wood for the manufacture of furniture is obtained from
(a) Cedrus deodara
(b) Pinus longifolia
(c) Dalbergia sissio
(d) Mangifera indica
1822: Most of the explosions in mines occur due to the mixing of
(a) hydrogen with oxygen
(b) oxygen with acetylene
(c) methane with air
(d) carbon dioxide with ethane
1823: With reference to the scientific progress of ancient India, which of the statements given below are correct?
1. Different kinds of specialized surgical instruments were in common use by 1st century AD.
2. Transplant of internal organs in the human body had begun by the beginning of 3rd century AD.
3. The concept of sine of an angle was known in 5th century AD.
4. The concept of cyclic quadrilaterals was known in 7th century AD.
Select the correct answer using the codes given below :
(a) 1 and 2 only
(b) 3 and 4 only
(c) 1, 3 and 4 only
(d) 1, 2, 3 and 4
1824: Which one of the following is the best description of the term 'ecosystem'?
(a) A community of organisms interacting with one another.
(b) That part of the Earth which is inhabited by living organisms.
(c) A community of organisms together with the environment in which they live
(d) The flora and fauna of a geographical area
1825: Assertion (A):
Information technology is fast becoming a very important field of activity in India.
Reason (R):
Software is one of the major exports of the country and India has a very strong base in hardware.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is not a correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true