MCQ
Purines possess nitrogen at which position?
- A1, 2, 4 and 6 position
- B1, 3, 5 and 7 position
- C1, 3, 7 and 9 position
- D1, 2, 6 and 8 position
Explanation:
Purines consist of a six-membered and a five-membered nitrogen containing ring, fused together. It possesses nitrogen at 1,3,7 and 9th position.

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$R$ - Plants comprises more than $22$ percent species.
$I$. Removal of $80\; \%$ tigers from an area resulted in greatly increased growth of vegetation.
$II.$ Removal of most of the carnivores resulted in an increased population of deers.
$III.$ The length of food chains is generally limited to $3$ to $4$ trophic levels due to energy loss.
$IV.$ The length of food chains may vary from $2$ to $8$ trophic levels.
Which two of the above statements are correct?
