of a following passage and related studied concepts:

Direction (Q. No 1-4). Answer the questions on the basis ofyour understanding

signals. It was a Dusshera night and there

(1) Vikas house is very near to a main road crossing having traffic
All the neighbours of Vikas and othe r
was a big traff ic jam on the main road just outside his house.
ents were also burs ting crackers and enjo ying man y othe r types of fireworks. Vikas's 70
colony resid
taken ill suddenly. She complained of
year old grandmother, who was watching the fireworks, was
ulty in brea thing and also felt naus ea and head ache . Vika s's grandmother was rushed to a nearby
diffic
whe re the doct ors mad e her inhale som e med icine and then put her on oxygen for some time.
hospital
his grandmother to remain inside the
Vikas's grandmother recovered fairly quickly. The doc tor advised
e for that nigh t with all the door s and wind ows close d. The doctor also asked her to buy a small,
hous
felt suffocated again.
portable oxygen gas cylinder and use it to breathe at home if she
?
(i) Wha t deficiency was caus ed in the body ofV ikas 's gran dmo ther
was only Abh ishe k's gran dmo ther
(ii) Whi ch syst em/ bod y part of gran dmo ther got affe cted ? Why
affected?
(iii) Wha t mad e Vikas-s gran dmo ther sudd enly ill ?
(iv) Give two reasons for this cond ition of Vikas's gran dmo ther.
from the blood. It is used whe n the kidney
(2) A dialysis machine is a machine designed to remove wastes
or whe n bloo d acidity, urea , or pota ssium levels incre ase much above normal. In kidn ey dialysis,
fail,
eable membranes.
blood flows through a system of tubes composed of partially perm
 Dialysis fluid (dialysa te) has a Dialyzer inflow pressure monitor
Venous
compos ition similar to blood pressure monitor
except that the concentration of
. . h
wastes 1s low. It flows in t e Heparin pump
(to prevent
opposite direction to _the ~lood on clotting) t
Dialyzer
the outside of the d1alys1s tubes. (Filter) t
Consequently, waste products like
urea diffuses from the blood into
Air detector
the dialysis fluid, which is
t
..
clamp
constan tly replace. The dialysis
fluid flows at a rate of several 100 Filtered blOOd
cm per minute over a large surface returned to
Arterial
Pressure monitor
t 1
• body
area. For some people dialysis is
an ongoing procedu re, but for
Blood pump
others dialysis just allows the
kidneys to rest and recover. Blood removed for dialysis
(i) In kidney dialysis, explain why the dialysing solution is constant ly replaced rather than being
recirculated?
(ii) What is the best long term solution for kidney failure?
(iii) Give a reason why the dialysing solution flows in the opposite direction to the blood.

(3) Following are based on the two tables given below. Study these tables related to blood sugar
levels and
answers the questions that follows. (CBSE Sample paper 2020)
Table 1 (Blood glucose chart)
Mean Blood Glucose Level (mg/ dL)
Doctor's advice needed 380
350
315
280
250
215
Good 180
150
Excellent 115
80
so
Table 2 (Blood Report of Patient A and B)
Time of check Blood glucose ranges (mg/ dL)
Patient A Patient B
Before breakfast (Fasting) < 100 70 - 130
Before lunch, supper and snack < 110 70 - 130
Two hours after meals < 140 < 180
Bedtime < 120 90 - 150
 (i) Identify the hormone whose level in the blood is responsible for the above disease.
(ii) Refer to the Tabl~ 1 and suggest the value of the mean blood glucose level beyond which doctor's
advice is necessary.
(a) 180 mg/dL (b) 115 mg/dL
(c) 50 mg/dL (d) 80 mg/dL
(iii) Refer to Table 2, showing the blood report of the level of glucose of patients A and B. Infer the
diseases which can be diagnosed from the given data
(iv) Which one of the following diets would you recommended to the affected patient?
(a) High sugar and low fat diet. (b) Low sugar and high protein diet.
(c) High Fat and low fiber diet. (d) Low sugar and high fiber diet.
(4) All living cells require energy for various activities. This energy is available by the breakdown of simple
carbohydrates either using oxygen or without using oxygen. (CBSE Sample paper)
(i) Energy in the case of higher plants and animals is obtained by
(a) Breathing (b) Tissue respiration
(c) Organ respiration (d) Digestion of food
(ii) The graph below represents the blood lactic acid concentration of an athlete during a race of 400 m and
shows a peak at point D.
Respiration in athletics
The blood of an athlete was tested before, during and after a 400m race:

12 D

-10
Blood lactic
acid
8
concentration
nmol/litre 6

0 L-----~3=-=0------;;6~0
0 time in seconds
Lactic acid production has occurred in the athlete while running in the 400 m race. Which of the
following processes explains this event? . . .
. . t' (b) Anaerobic respiration
(a ) A erob 1c resprra 10n
. (d) Breathing
(c) Fermentation . d 'th t to the time while an
(iii) Study the graph below that represents the amount of energy supp 1te wt respec
athlete is running at full speed.
100 - - - - - - - plot A

~ 75
~
-0
-~
a.
§- 50
en
>,
en
~ 25 - - - - - plotB
UJ

1 3 ~
Time running at full speed (min)
 Choose the correct combination of plots and justification provided in the following table.
PlotA PlotB Justification
a) Aerobic Anaerobic Amount of energy is low and inconsistent in
aerobic and high in anaerobic
b) Aerobic Anaerobic Amount of energy is high and consistent in
aerobic and low in anaerobic
c) Anaerobic Aerobic Amount of energy is high and consistent in
aerobic and low in anaerobic
d) Anaerobic Aerobic Amount of energy is high and inconsistent in
anaerobic and low in aerobic
(iv) The characteristic processes observed in anaerobic respiration are
(A) presence of oxygen ( B) release of carbon dioxide
(C) release of energy (D) release of lactic acid
(a) (A), (B) only (b) (A), (B), (C) only
(c) (B), (C), (D) only (d) (D) only
( v) Study the table below and select the row that has the incorrect information.
Aerobic Anaerobic
a) Location Cytoplasm Mitochondria
b) End Product CO2 and H 20 Ethanol and CO2
c) Amount of ATP High Low
d) Oxygen Needed Not needed
Direction (Q No 1-3). Answer the questions on the basis of your understanding of a following passage and related studied
concepts:

(1) A receptor is a specialised cell or a group of cells in a sense organ that perceive a particular type of
stimulus in the environment like light, heat, pressure, etc. Different sense organs having different
receptors for detecting different stimuli.
Name of Recepers Stimulus Location in our body
,- · - ,-
Light
~

Eyes
-
Photo receptors
Phonoreceptors Sound Inner Ears
Olfactory receptors Smell Nose
Gustory receptors Taste Tongue
Thermoreceptors Heat/Gold /
Skin
Tangorecepters Touch Skin

Receptors are either neuron endings or specialised cells that are in close contact with neurons endings
to perceive information about their external or internal environments. The receptors cells receive
stimulus from the environment and transform these excitations into electro-chemical impulse.
Therefore, all the receptors in various sense organs receive stimuli from the surrounding environment
and send messages to the spinal cord and brain through sensory nerves. Another type of nerve cells
called motor nerves transmit the response from the sensory organs to central nervous system towards
effectors, in the form of electrical impulse.
(i) Upon receiving a signal the dendrite tip of a nerve cell sets off a chemical reaction that
(a) creates an electrical impulse in the next neuron
(b) creates an electrical impulse in the dendrite
(c) creates a stimulus
(d) releases some chemicals in the cell body of the neuron
(ii) When stimulated by a stiinuli, the nerve impulses are
(a) continuously discharged
(b) discharged for a short time
(c) discharged at a high rate initially and declines later
(d) discharged at different rates depending on the type of receptor
(iii) What is a nerve impulse?
(2) The endocrine system regulates the body's processes by releasing
chemical messengers (hormones) into the bloodstream. Hormones are
. . .
potent chemical regulators. They are produced in minute quantities yet / .1ood glucose"'-
can have a large effect on metabolism. / ~ses : insulin :s ' \
Raises released Lowers
The endocrine system comprises endocrine cells (organized into blood blood
endocrine glands), and the hormones they produce. Unlike exocrine glucose glucose
IeveI level
glands (e.g. sweat and salivary glands), endocrine glands are ductless Blood glucose
glands, accreting hormones dir_ectly into the bloodstream rather than falls: glucago" /
is released
through a duct or tube.
Some organs (e.g. the pancreas) have both endocrine and exocrine
regions, but these are structurally and functionally distinct.
\
-j:;:,
 The basis of ho rm on al co nt ro l
an d th e role of negative fe ed ba
levels ar e de sc rib ed below. ck mechanisms in re gu la tin g ho
rm on e
(i) 'W hy is th e sp ee d of ho rm on al
responses slower?
(ii) Ho rm on es affect only specifi
c ta rg et cells. State tru e or £lase .
(iii) W ha t is co m m on in bo th in
su lin an d glucagon?
(iv) Am on g en do cr in e gl an ds
an d exocrine, which have ducts?
l3) some plants like pea_ pl an t c\im_b_ up
ot he r plants or fences by means Tendrils (for
tendrils. Th es e te nd nl s ar e se ns ,tw of support and
e to touch. When th ey ca m e in co
with any su pp or t, th e pa rt of th nt act climbing)
e tendril in contact with th e objec
not grow as rapida\\y as th e pa rt t do es
of th e tendril away form th e objec
causes th e ten dr il to circle ar ou t. This
nd th e ob jec t find this cling to it.
commonly, pl an ts re sp on ds to sti More
muli slowly by growing in a parti
direction. Because th is gr ow th in cular
directional, it appears as if th e pl
moving. ant is
(i) W ha t he lp s th e pl an ts to cl Sw ee t Pe a
im b up any fence or cover up othe
(ii) H ow te nd ril cl in g to an y ob r plants?
ject.
(iii) Th e gr ow th of th e pl an t is
directional (True/False).
(iv) Gi ve on e ex am pl e of th e
pl an t wh ic h cling to other plants or
fence.
Direction (Q No 1-4). Answer the questions on the basis of your understanding of a following passage and related studied
concepts:

(1) Radha is a married woman having two children. She does not want to have any more children. Her
husband also supports her decision not to have more children. They are both happy with just two
children, both of whom are daughters.
(i) Suggest any two types of birth control methods which Radha and her husband can make use of to
avoid pregnancy. Explain how these methods work to prevent pregnancy.
(ii) Which birth control method has additional advantage of giving protection from sexually transmitted
diseases (STDs)?
(2) AIDS is a chronic life-threatening disorder. It is also a
Symptoms of HIV infection
sexually transmitted disease, caused by a virus called
HIV (Human immunodeficiency Virus). AIDS damages the ! -=;::;- - Headache
and difficulty
body's immune system, so that the body cannot protect Lymph node concentrating
itself against infection. So. AIDS is a very dangerous
disease which leads to death.
(swelling)
- Skin
- rashes
Respiratory _....;...._·':lll
Early symptoms of AIDS are weight loss, fever, diarrhoea, - fever
system - night sweats
oral thrush and enlargement of lymph glands. In severe - dry cough
conditions, a patient may develop pneumonia, cancer
of skin and lymph system. The patient dies within a year.
- pneumonia
- sore throat
~"'F~-------- Digestive
system
- nausea
AIDS is transmitted by blood transfusion, hypodermic - vomiting
Musel
- diarrhea
needles used by addicts, homosexual or heterosexual - pain

intercourse. '--..._ Nail

(thickening
Treatment : No definite cure has been found for the AIDS and curving)
Joints
disease so far. The best method of prevention is to avoid - pain
drug abuse and intercourse with affected persons.
Weight loss
(i) Contraceptive methods can be used to prevent and fatigue
STDs. Name any three.
(ii) How can people be made aware of STDs?
(iii) What are sexually transmitted diseases?
(iv) How are general growth and sexual maturation different from each other?
 · h t rt happening in their bodies under
(3) As soon as boys and girls reach adolescent age, certain c anges s a t d t h • ht
. . b d" Th changes are most 1
y re 1a e o e1g '
the influence of sex hormones produced in their o 1es. ese -
size, voice, pitch, physical attributes etc.
The table below shows the average height of boys and girls up to the age of lS years.

Age/Years Average Height/cm

Boys Girls
0 (at birth) 52 51
1 76 75
2 88 88
3 97 97
4 103 103
5 110 110
6 118 117
7 125 122
8 131 128
9 135 133
10 141 140
11 145 146
12 150 153
13 156 158
14 164 161
15 169 162
16 172 162
17 174 162
18 175 162

(i) State the changes happening in adolescens boys and girls.

(ii) Significant spurt in increase of height boys occurs at the age of
(a) 11-12 years (b) 13-15 years
(c) 16-17 years (d) 17-18 years
(iii) The increase in height in girls almost ceases at age of
(a) 14 years (b) 17 years
(c) 16 years (d) 15 years
(iv) When does the most rapid growth take place?
(4) The growing size of the human population is a cause of concern for all people. The rate of birth and
death in a given population will determine its size. Reproduction is the process by which organisms
increase their population. The process of sexual maturation for reproduction is gradual and takes place
while general body growth is still going on. Some degree of sexual maturation does not necessarily
mean that the mind or body is ready for sexual acts and bringing up children. Various contraceptive
devices are being used by human being to control the size of population. (CBSE 2020)
 (i) List two comm on signs of sexual matu ratio n in boys and girls.
(ii) Wha t is the result of reckless female foeticide?
(iii) Whic h contraceptive meth od changes the hormonal balance of the body
?
(iv) Writ e two factors that determine the size of a population.
 tom ~ehension/tase 5a~e Ouestions
1-3) . Answer the questions on the basis of your understanding of a following passage and related studied
Direction (Q. No
concepts:
ronment
is much more likely to adopt to human caused envi
(1) An ecosystem that retains a high biodiversity
change than in one that has a little .
Consider the two food webs shown below.
Food Web B
Food Web A
Wattle Tea tree Wattle
Eucalyptus

l l l
Leaf hopper Butterfly larvae
l
Leaf hopper
Beetie

l~ >< J: >< l
Spider Wasp Honey eater
l
Wasp

ul> ;;oL /j ~
Lizard
l
Jb
l
~
l l~
Butcher Bird
Na_!Lve Cat
____ .-
Native Cat

Snake Snake Butcher bird ~

biodiversity, where at some levels the food path

Food web B represents a situation with very low lt,
A represents a more diverse ecosystem as a resu
involves only a single type of organism. Food web
. Generally, loss of biodiversity should be regarded
there are many more alternative feeding pathways but
s that have become extinct represent a big loss
as a serious issue, not only because the organism
me more exposed to extinction in the future.
also because the organisms that remain have beco
(i) Flow of energy in an ecosystem is always
(a) undirectional (b) mult i directional
(c) bidirectional (d) no specific direction
leaf hopp ers died out in both locations, wha t would
(ii) Food webs A and B are in different locations. If
be the effect on the food webs?
a green plan t. Why ?
(iii) The first trophic level in a food chain is always
edia te food sources. Whi ch two animals are they?
(iv) In food web A only two animals have three imm
tion in the
(2) Following is a hypothetical example. In the
forests of a mainland, jungl~ fowls showed varia
were bette r camouflaged from their predators than
colour of their feathers. Fowls with brown feathers
land more number of brown-feathered fowls were
those with bright red feathers. Thus, in the main s to a
A person transported a few red-feathered fowl
observed as compared to the bright red ones.
 nearby island tha t did no t have any jungle
fowls. Also, there were no predators for
Aft er several years, the island had more red the jungle fowl.
-feathered fowls than brown-feathered fow
(i) Th e observed variation in the frequency ls. (NTSE 2016)
of red and brown-feathered in island as com
mainland is du e to pared to the
(a) ada pta tio n (b) natural selection (c) genetic dri ft (d) competition
(ii) Fowls wit h bro wn feather were better . Ca
mouflaged from their pretators tha n those wit
feathers? Wh at is process called. h bri ght red
(3) Surbhi is a married woman who has a cle
ft chin (a deep
hollow in her chin). Surbhi has recently been bles
sed with a
baby girl who has also a cleft chin. Deepali is a clos
e friend
of Vidya. When she learnt that Surbhi's baby gir
l also has
a cleft chin like Surbhi . she got worried. This
Deepali has a huge scar on her left cheek which
is because
remains
LJ LJ
penn.anently after she got a cut on the cheek dur
ing an
accident which look place in her school days. De
worried that her baby (which is due shortly), epali is
may also Cle ft chi n pre sen t Cle ft chin abs ent
have a scar on her left cheek jus t like her. One day
, Deepali niece Luxmi, who is a science student of
came to see her. Deepali shared heT apprehension class X,
with Luxmi. Luxmi could understand heT problem.
Deepali that heT case is entirely different from She told
that of Surbhi . I explained everything to Deepa
Deepali was now very mu.ch relaxed . li clearly.
(i) Wh at typ e of tra it is (i) cleft chin, and (ii)
cheek scar?
(ii) Ex pla in why, Vidya's de ft chin has bee
n passed on to her baby bu t Anita's cheek sca
passed on to her baby. r cannot be
(iii) Wh at is an acquired trait?
(iv ) Wh at is an inherited trait?
 C,o~ f"ehension/tase ase uestions ·
following passage and related studied
Direction (Q. No 1- 3). Answer the questions on the basis of your understanding of a
concepts :
is the main component. Food as
(l) Human body is made up of five impor tant components, of which water
is obtained from plant through
well as potable water are essential for every human being. The food
the fields. These pesticides are
agriculture. Pesticides are being used extensively for a high yield in
from the water bodies these
absorbed by the plants from the soil along with water and minerals and
als are not biodegradable,
pesticides are taken up by the aquatic animals and plants. As these chemic
ntration of these chemicals
they get accumulated progressively at each trophic level. The maximum conce
and body. (CBSE 2020)
gets accumulated in our bodies and greatly affects the health of our mind
(i) Why is the maxim um concentration of pesticides found in human beings
?
(ii) With regard to various food chains operating in an ecosystem, man is
a:
(a) Consu mer (b) Producer (c) Produ cer and consumer
(d) Producer and decomposer
des throug h food to some
(iii) Give one metho d which could be applied to reduce our intake of pestici
extent.
(iv) Various steps in food chain represents:
(a) Food web (b) Troph ic level
(c) Ecosystem (d) Bioma gnific ation
ys. When she went to the fields
(2) Rekha visited her village with her parents during the winter holida
ng crops in the fields. When she
outside the village, she saw a farmer spraying pesticides over the standi
it was a pesticide which had
looked at the container of pesticides lying on the ground, she knew that
g pesticides withou t taking any
been banned from use in most of the countries. The farme r was sprayin
rly with a cloth while spraying
precautions. Shivani asked the farmer to cover his nose and mouth prope
crops because it is harmful for
the pesticides. She also asked him not to spray too much pesticide on the
ted the farmers about various
human beings, other animals and aquatic life in long run. Shivani educa
harmful effects of pesticides.
pestici des was being sprayed
(i) What are pesticides? Why are pesticides sprayed over the crops? Which
by the farmers on the crops.
(ii) (a) At which trophic level pesticides enter a foodchain?
um?
(b) At which trophic level of food chain the concentration of pesticides are maxim
 ··· • . · t · ·des in the body of living organisms at
(nt) What name 1s given to the process of concentration, on pes 1c1
each trophic level of the food chain?
(iv) Why do pesticides get accumulated at each trophic level in a food chain?
(v) What are the harmful effects of pesticides being sprayed by this farmer?
(3) Certain substances in the environment are harmfu l when -~-~~-:::-~ ~~~-~-~-~~~~~~~~~-~~a1~~~
absorb ed in high concen trations . Substances, such as ~ iJ)l i_- -· CAU TION ~,
pesticides, radioactive isotopes, heavy metals and industrial
chemicals such as PCBs can be taken up organisms via their lllrii1
I pQ B
~ •; ·, C~NT.AINS §
~
food or simply absorbed from us surrounding medium. S ~
.5 .' 5I
~ ·t i , · ,
The toxicity of a pesticide is a measure of how poisonous (PolYchlorlna_tecU~!phenyls)
t he chemicaI is, not only to the target organisms, but non- ~ A'toxtc envtronmental contaminant requiring
~ ,pecw handling anc1 c1epa•a11n ■ccordance with
target species as well. The specific ity (broad narrow ~ u.s.env~rnemaf P~AgencyRegutatton■ ~
spectru m) of a pesticide describes how selectively is in • ~ ~
40 c~ 781. For ~Inform ation Contacl
· .tt1enearNtu.s.e.P.A.Offlce.
~
~
targeting a pest. An important issue relating to the use of a § ~
pesticid e is its persiste nce; how long it remain ing the
environ ment.
5- u.s.coutGuar:,::::---
1ncaNotaccktentorap1n.ca11~0111rwt11e

~ Ataoeo~ct- - - - - - - - - 5
I
A pesticide may be biodegradable or resistant biological ~.~~.......... ..~~~~~~~
breakdown. Many highly persistent pesticides cannot be ~~.......... ......~ ..~-.~
metabolised or excreted. (CBSE 2020) .
(i) Name few environment hazardous substances.
(iv) What is toxicity?
(iii) Which among the following is non-bio-degradable substances?
(a) Rubber (b) Wood (c) Leaves (d) Paper
(iv) Which amongst the following is not hazardous for the environment?
(a) Pesticides (b) Fertilizers (c) Heavy metals (d) Manure s