Q18 of 30 Page 1

(a) From the following group of organisms create a food chain which is the most advantageous for Human being in terms of energy.

Hawk, Rat, Cereal plant, Goat, Snake, Human Being


(b) State the possible disadvantage if the cereal is growing in soil rich in pesticides.


(c) Construct a food web using the organisms mentioned above.


OR


(a) Write two harmful effects of using plastic bags on the environment. Suggest alternatives to the usage of plastic bags.


(b) List any two practices that can be followed to dispose off the waste produced in our homes.


(a)



(b) Pesticides are not easily metabolised and hence accumulate. Upon consumption by the higher trophic levels their concentration will increase across the trophic levels. Hence, we will find biomagnification across trophic level. The levels will be highest in humans.


(c)



OR


(a) Two harmful effects of using plastic bag:


1. It cannot decompose


2.it produce harmful gasses on burning


To alternative of plastic bags:


1. Jute bags


2. Cotton handmade bags


(b) Two practices that can be followed to dispose off the waste produced in our homes:


1. Practice to recycling the waste


2. By reusing it


More from this chapter

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16

Complete and balance the following chemical equations:

(i) NaOH(aq) + Zn(s)→


(ii) CaCO3(s) + H2O(l) + CO2(g)→


(iii) HCl(aq) + H2O(l)→


OR


During electrolysis of brine, a gas ‘G’ is liberated at anode. When this gas ‘G’ is passed through slaked lime, a compound ‘C’ is formed, which is used for disinfecting drinking water.


(i) Write formula of ‘G’ and ‘C’.


(ii) State the chemical equation involved.


(iii) What is common name of compound ‘C’? Give its chemical name.


 17

Study the data of the following three categories A, B
and C.




(i) From the given three categories A, B and C, pick the one which forms Dobereiner Triads.


(ii) Why did Mendeleev laced elements of category A, B and C in three different groups?


(iii) Is Newland law of octaves applicable to all the three categories? Give reason to justify your answer.


 19

(a) State the role played by the following in the process of digestion.

(i) Enzyme trypsin


(ii) Enzyme lipase


(b) List two functions of finger like projections present in the small intestine.


 20

(a) Classify the following as homologous or analogous pairs:

(i) Broccoli and cabbage


(ii) Ginger and Raddish


(iii) Fore limbs or birds and lizard


(iv) Wings of a bat and wings of a bird


(b) State the main feature that categorises a given pair of organs as homologous and analogous.