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Biology · 2024 · 3 marks
CBSE 2024 · Region 1 · Set 2 · Q28
(a) State what is primary productivity and mention its units. 1 1/2 (b) Some ecologists observed that primary productivity of a place in Rajasthan…
(a)
State what is primary productivity and mention its units. $\displaystyle 1 \frac{1}{2}$
(b)
Some ecologists observed that primary productivity of a place in Rajasthan was low as compared to a particular place in Kerala. Explain why. $\displaystyle 1 \frac{1}{2}$
Marking-scheme solution
(a)
-Primary productivity – It is the amount of biomass or organic matter produced per
unit area over a time period by plants during photosynthesis
weight (gm–$\displaystyle 2$) or energy (kcal m -$\displaystyle 2$ )
-Rate of biomass production by producers
-(gm–$\displaystyle 2$ yr–$\displaystyle 1$) or (kcal m–$\displaystyle 2$) yr–$\displaystyle 1$
(b)
Primary productivity of a place in Rajasthan is low due to following factors
-lesser number of plant species at the particular place in Rajasthan
lower availability of nutrients in Rajasthan.
-lesser photosynthetic capacity of plants in Rajasthan
-Unfavourable environment like water scarcity or high temperature etc. in Rajasthan .
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