CLASS 10 JUNE, 2019 solved paper of : SCIENCE ( Biology )

S. S. L. C. EXAMINATION, JUNE, 2019

Subject : SCIENCE ( Biology )

2. The group of organisms that reproduce through fission only is

(A) Amoeba, Hydra, Spyrogyra

(B) Leishmania, Amoeba, Yeast

(D) Plasmodium, Amoeba, Leishmania.

Ans. : (D) — Plasmodium, Amoeba, Leishmania

3. The correct statement related to digestion in small intestine is

(A) acidic food is made alkaline by bile juice

(B) food is made acidic by hydrochloric acid

(D) protein is digested due to the action of pepsin.

Ans. : (A) — Acidic food made alkaline by bile juice

5. Observe the food chain given below :

Grass → Grass hopper → Frog → Snake → Eagle.

If the energy available at first trophic level is 5000 J, then the amount of energy available for snake is

(A) 500 J (B) 5 J

Ans. : (B) — 5 J 1

10. Observe the table which shows contrast forms of pea plants ?

Colour of the seed Position of the flower

Green ( G ) Axial ( A )

Yellow ( g ) Terminal ( a )

The genetic makeup with green seed and terminal flowers is indicated as

(A) gGAa (B) GgAa

Ans. : (D) — Ggaa 1

13. Name the products of anaerobic respiration.

Ans. : Ethanol. Carbon dioxide.

16. Micro-organisms like bacteria are called decomposers. Why ?

Ans. : 1. Break down the complex organic substances into simple inorganic substances.

2. Break down dead remains and wastes of organisms.

18. Name the factors responsible for speciation.

Ans. : Variations 2 1 Geographical isolation.

21. Draw the diagram showing opened stomata. Label the following parts :

(i) Guard cells

(ii) Stomatal pore. Ans. :

14. Diagram showing opened stomata :

23. Diagrams given below represent hearts of three different animals. Observe it and answer the question.

Among these, which heart is helpful to the animals that require more energy ? Why ? OR

The approximate lengths of small intestine of animals x and y are given in the table. Observe it and answer the question.

Identify the herbivorous and carnivorous animals in the table and support your decision with scientific reasons.

Ans. : (i) Heart –

(ii) Oxygenated and deoxygenated blood will not mix together Efficient supply of oxygen to the body. 2 Helpful to maintain body temperature. OR

x → Herbivore y → Carnivore.

1. Herbivores require a longer small intestine to digest cellulose.

2. Small intestine of carnivores is short as the meat is easier to digest

27. Draw the diagram showing the structure of neuron. Label the following parts : (i) The part which has prominent nucleus (ii) Dendrite.

Ans. : Diagram showing structure of neuron.

29. In sustaining reproductive fertility of a person,

(a) position of the testis in the body

(b) secretion of the testosterone

Ans. : (a) Sperm formation requires a lower temperature than body temperature.

(b) Testosterone regulates / stimulates the formation of sperm.

Thus reproductive fertility is sustained by the formation, stimulation to the formation and proper transportation of sperms.

33. Draw the diagram showing the germination of pollen on stigma and label the part on which pollination takes place.

Ans. : Diagram showing germination of pollen on stigma :

36. Imagine the following situations :

(i) Clapping at the end of a programme

(ii) Fluctuating blood pressure in the body. How these situations are functionally different ? Give reason. OR

“We withdraw our leg when stepped on thorn unknowingly.”

(a) Trace the sequences of events which occur in this action.

(b) Which part of human nervous system controls this action ?

Ans. : (i) Voluntary action :

1. Based on deciding what to do next ( Action performed based on thinking )

2. Controlled by forebrain.

(ii) Involuntary action :

1. Action without thinking control

2. Controlled by hind brain.

(a) (i) Receptors receive the stimulus of pain

(ii) Messages reach spinal cord through sensory neuron.

(iii) Responses reach motor neuron through association neuron.

(iv) Responses reach effector through motor neuron.

(v) Muscles withdraw the leg.

(b) Spinal cord

39. (i) How does combustion of fossil fuels cause greenhouse effect ?

(ii) List the reasons for failure in sustaining ground water. OR

(i) Reuse of plastic products is better than recycle method. Why ?

(ii) “Local people are stakeholders of forest resources.” Explain.

Ans. : (i) Releases carbon dioxide Increases global worming

(ii) 1. Deforestation

3. Growing crops which demand high water

4. 3. Pollution due to industrial effluents

5. Pollution due to urban wastes.

6. mber and Thatch.

7. For bamboo used in huts & baskets

8. For implements of agriculture, fishing and hunting.

9. To gather fruits, nuts and medicines.

10. To fodder for their cattles

42. (i) How does relative method help to determine the age of fossils ?

(ii) “Experiences of an individual during its life time cannot direct evolution.” Why ?

(iii) “Chromosomes inherited from the father determines the sex of a child.” Explain.

Ans. : (i) Gives the information that, fossils which are closer to the surface are most recent than those in deeper layers. 1

(ii) A. Change in non-reproductive tissues cannot be passed on to the DNA of germ cells.

B. Experiences gained by the organism is not transferred to the DNA and cannot be transferred to the next generation. ( Any one ) 1

(iii) All children will inherit an X chromosome from mother.

1 Child who inherit an X chromosome from father will be a girl.

2 Child who inherit an Y chromosome from father will be a boy.

Milan Tomic

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