Marking scheme of 9th preboard (Thankful to Ansh Mittal 9th E for making this document)

Biology Answer Key ( Class- 9^th)

Q-1  Mention two food requirements of milch animals.

 Ans-1 Roughage and Concentrate

Q- 4  Which organelle is involved in formation of lysosomes ?

 Ans-4 Golgi apparatus

Q-11 Write symptoms when following organs are targeted by microbes ?

                                               OR

1. Give two examples of air borne diseases

2. Why does a person suffering from aids dies even due to small infection ?

3. In many species of mosquitoes, the males do not prefer human blood but females do. State   Why?

Ans-11 (a) Lungs - Cough and breathlessness

             (b) Liver  - Jaundice and our body will become pale

             (c) Brain - Headaches, vomiting , fits or uncousciousness

                                              OR

1. Influenza and tuberculosis

2. Aids is a complex of diseases. Its pathogen HIV virus weakens our immune system and damages its function. That’s why every small cold can become pneumonia  and a minor gut like infection can produce diarrhea . Ultimately, these infections kill the people.

3. Female mosquitoes prefer human blood because they need human warm blood for nourishment of themselves and to lay eggs while males do not have such requirement.

Q-12 What are the consequences of following conditions ?

Ans-11 (a) When a cell contains higher water concentration than its external surroundings, it will loose water to its external surroundings due to osmosis and will become shrink

 (b) When a cell contains lower water concentration than its external surroundings, it will gain water from its external surroundings due to osmosis and will swell up

 (c) When a cell has equal water concentration than its external surroundings, then there is no net movement of water and a cell remains unaffected.

Q-18 A student visited a fish farm where he found catla, rohu, mrigals, common carps and grass carps cultured in same pond

(a) Name the type of fish farming observed by student

(b) What is the main problem in such farming ?

 (c)  How do farmers overcome such problems ?

Ans-18 (a) Composite fish culture

(b) One problem with this type of fish culture is that these fishes breed only in monsoon season. So a major problem is lack of availability of good quality seed.

 (c) Farmers overcome such problems by introducing hormonal stimulations on fishes

Q-19 What precautions can you take in your school to reduce the incidence of infectious diseases?

Ans - I will spread awareness about the consequences of infectious diseases. I will ensure that every child washes his hand before eating and after eating his/her food. I will advice our canteen manager to not to sell stagnant food and  I will also advice an affected child to take leave from school so the disease wont’t spread.     

Q-23 (a) In the table given below are the names of some plants. Write their division and also identify the odd plant of the group

PLANTS	DIVISION	ODD MEMBER
(1) bacteria, yeast, paramecium, euglena (2) Spirogyra, chara, ulva, mushroom, laminoria (3) zarnia, pinus, equistem, cycas

      

(b) Who introduced the system of nomenclature ?

(c) Rana tigrina is the scientific name of frog, what do these two terms imply

                                               

   OR

Identify the phylum of kingdom animalia in which animal has

(a)  a pseudocoelom

(b) a water driven tube system

(c) jointed legs

(d) pores in the body leading to canal system

(e) notochord at some stages of their life

Ans-23 (a)  

PLANTS	DIVISION	ODD MEMBER
(1) bacteria, yeast, paramecium, euglena (2) spirogyra, chara, ulva, mushroom, laminoria (3) zarnia, pinus, equistem, cycas	unicellular Algae Gymnosperms	Bacteria Mushroom Equistem

(b) Carolus Linnaeus

(c) Rana is the genetic name of the common frog and tigrina is the specific name of the common frog

                                             OR

(a) Nematoda

(b) Echinodermata

(c) Arthropoda

(d) Porifera

(e) Protochordata

Q-25 (a) Draw a diagram of cardiac muscle and label any two parts.

(b) Name the following

          1. Living tissue that provides mechanical support to plants

            2. Animal tissue with elongated cells and contractile proteins  responsible for movement

            3. Highly specialized cells for being stimulated and then transmitting the stimulus very rapidly

Ans-25 (a)

 (b) 1. Collenchyma

                 2. Muscle tissue

                 3. Neuron

Q-26 What is used while preparing a temporary mount of human cheek cells and why ?

Ans-26 Glycerine, cover slip and methylene blue are used in preparing a temporary mount of human cheek cells. Glycerine protects that cheek cell from being dehydrated and keeps them wet. Methylene blue is used for staining.  Nucleus and cytoplasm take the stain and are visible under microscope. Cover slip is used protect cell from getting  direct contact with microscope and prevents fungal infection on cell.

Q-27 You have been given two slides of collenchyma and sclerenchyma. How will you identify them on basis of cell wall and nucleus ?

Ans -27 Cell wall of collenchyma is made up of cellulose and is thickened at corners whereas cell wall of sclerenchyma are thick but are lignified. Collenchyma nucleus is prominent at the periphery with cytoplasm but the centre of the cell consists of vacuole and sclerenchyma lack as these cell are dead or sometimes have very undeveloped nucleus.

Q-28 Coakroach belongs to which phylum ? Write any two identifying features of the phylum.

Ans-28 Coakroach belongs to phylum Arthropoda. Its features are

1. It have joint appendages

2. It's body has well developed head and distinct eyes