Question 1

Question 1(i)Adrenaline is a 'stress hormone' found in humans similarly the 'stress hormone' of plant isethyleneabscisic acidcytokininsauxin

Accepted Answer

abscisic acidReason — Abscisic acid is the plant hormone that helps the plant to survive in unfavourable conditions. They cause closure of stomata and also inhibit growth.

Question 2

Question 1(vi)Assertion (A) An average adult have about 5-6 litres of blood by volume in his body.Reason (R) The main functions of the blood in our body are transportation and protection.Both A and R are trueBoth A and R are falseA is true and R is falseA is false and R is true

Accepted Answer

Both A and R are trueReason — An average adult has 5-6 litres of blood by volume in his body. The main functions of the blood are transportation and protection.

Question 3

Question 1(xi)Harish went to the beach for vacation of 2-3 days. After coming home he noticed his skin tone has darkened. This was due tomelaninrhodopsinthyroxineserotonin

Accepted Answer

melaninReason — The darkening of Harish's skin tone after a beach vacation is primarily due to the increased production of melanin, a pigment responsible for skin color.

Question 4

Question 1(xiv)The external female genitalia is called thehymenuterusvaginavulva

Accepted Answer

vulvaReason — The external female genitalia is called the vulva.

Question 5

Question 2(i)Name the following.(a) General name of chemical substances which bring about control and coordination in plants.(b) The kind of lens required to correct myopia.(c) The prime source of chlorofluorocarbon is(d) The chromatin material is formed of(e) A pollutant which is mainly responsible for causing acid rain.

Accepted Answer

(a) Phytohormone(b) Concave lens(c) Refrigerant(d) DNA and histone protein(e) Sulphur dioxide (SO2)

Question 6

Question 2(ii)Arrange and rewrite the terms in each group in the correct order so as to be in a logical sequence beginning with the term that is underlined.(a) Ureter, Kidney, Renal artery, Urinary bladder(b) Intestine, Intestinal artery, Hepatic portal vein, Liver(c) Right auricle, Pulmonary artery, Vena cava, Right ventricle(d) Sperm duct, Sperm, Vagina, Urethra, Coitus.(e) Fertilisation, Gamete formation, Embryo, Zygote.

Accepted Answer

(a) Renal artery, Kidney, Ureter, Urinary bladder.(b) Intestinal artery, Intestine, Hepatic portal vein, Liver(c) Vena cava, Right auricle, Right ventricle, Pulmonary artery(d) Sperm, Sperm duct, Urethra, Coitus, Vagina(e) Gamete formation, Fertilisation, Zygote, Embryo

Question 7

Question 2(iii)Fill in the blanks with suitable words.The loss of excess water in the form of drops along the (a) ............... due to excessive (b) ............... is called guttation. In certain plants, like (c) ............... , grass etc. the root pressure is high enough to force the water all the way through the (d) ............... and comes out through the ends of (e) ............... .

Accepted Answer

The loss of excess water in the form of drops along the (a) leaf margins due to excessive (b) root pressure is called guttation. In certain plants, like (c) banana , grass etc. the root pressure is high enough to force the water all the way through the (d) stem and comes out through the ends of (e) leaf veins .

Question 8

Question 2(iv)Choose the odd one out from the following terms and name the category to which others belong.(a) Genotype, Phenotype, Allotype, Mutation(b) White matter, Duramater, Arachnoid matter, Piamater(c) Addison's disease, Cushing's syndrome, Adrenal virilism, Cretinism.(d) Mining, Stone drilling, Wearing of rubber tyres, Noise of jet(e) Cortisol, Aldosterone, Androgen, Epinephrine

Accepted Answer

(a) Odd one: AllotypeCategory: Others are genetic terms(b) Odd one: White matterCategory: Others are layers of meninges(c) Odd one: CretinismCategory: Others are abnormalities related with adrenal cortex hormones.(d) Odd one: Noise of jetCategory: Others are causes of particulate pollution(e) Odd one: EpinephrineCategory: Others are hormones of adrenal cortex.

Question 9

Question 2(v)Match the items given in Column I with the most appropriate ones in Column II and rewrite the correct matching pairs.Column IColumn IIFamily welfareAlkaline secretion into semenProstrate glandCopper-TIUDsRed triangleVasectomyDeath rateMortalityBirth rate Vas deferens

Accepted Answer

Column IColumn IIFamily welfareRed triangleProstrate glandAlkaline secretion into semenIUDsCopper-TVasectomyVas deferensMortalityDeath rate

Question 10

Question 3(ii)Mention two functions of placenta.

Accepted Answer

Two functions of placenta are:Acts as a barrier and prevents germs from entering foetal blood.Enables exchange of respiratory gases, nutrients and removes waste products of the foetus.

Question 11

Question 3(iii)What are differences between allosomes and autosomes?

Accepted Answer

AllosomesAutosomesAllosomes determine the sex of an organism.Autosomes determine the somatic traits.Allosomes are labelled with letters XY, XO, ZO, ZW.Autosomes are labelled with numbers.Allosomes difference in size, behaviour and form in males and females.There are same copies of autosomes in males and females.

Question 12

Question 3(iv)There is a need to check over-exploitation of resources. Explain.

Accepted Answer

The increasing human population is exerting pressure on limited resources essential for human growth, development, and well-being, necessitating a thorough examination of resource over-exploitation and its impact on ecological balance.

Question 13

Question 3(v)Draw a neat and labelled diagram showing the cross-section of an adrenal gland.

Accepted Answer

Below diagram shows the cross-section of an adrenal gland:

Question 14

Question 4(ii)Give two control measures of noise pollution.

Accepted Answer

Two control measures of noise pollution are:Use of sound absorbent material.Follow the norms of permissable sound.

Question 15

Question 4(iii)Explain systemic circulation.

Accepted Answer

It involves circulation of blood between the heart and the body organs (except lungs). It carries oxygenated blood to the body organs and returns deoxygenated blood back to the heart.

Question 16

Question 4(iv)Differentiate between embryo and foetus.

Accepted Answer

EmbryoFoetusIt is the early stage of development.After two months of gestation the embryo is called foetus.Limbs are not visible.Limbs are visible.

Question 17

Question 4(v)Draw a well labelled diagram of TS of artery and vein.

Accepted Answer

Below diagram shows the transverse section of artery and vein:

Question 18

Question 5(ii)After examining a prepared slide under high power microscope, a student concludes that the given slide shows stage of mitosis. Write his observation on the basis of which this conclusion can be drawn.

Accepted Answer

He might have observed the following:Formation of two cells from a cell.Chromosomes attached to spindle fibre and are arranged in a plane at equator.Splitting of sister chromatids in anaphase.

Question 19

Question 5(iii)Explain Darwin theory of 'Natural selection'.

Accepted Answer

During the struggle for existence, only those individuals which have advantageous variations survive while the ones which lack these variations are wiped out. Nature selects only those variations which are suitable for existence. This process is called natural selection.

Question 20

Question 5(v)Study the diagram given below and answer the questions that follows.(a) Name the parts labelled 1, 2 and 3 in the diagram.(b) Mention the collective terms for the membranes covering the brain.(c) What is the function of cerebrospinal fluid?

Accepted Answer

(a)A → CerebrumB → CerebellumC → Medulla oblongata(b) Meninges(C) The cerebrospinal fluid provides nutrition and protection against jerk to the brain.

Solved Sample Paper 4

Section A

Section B