KENDRIYA VIDYALAYA NO. 2 ,INF LINES JAMNAGAR
Sample Questions SA –II STD – X 2015-16
SUBJECT: SCIENCE (086)
QUESTIONS
Q1. Why does the clear sky appear blue ?How would the sky appear in the absence of earth’s atmosphere?
Q2.List two functions of each one of the following parts of human reproductive system.
a)
b)
c)
Testes
Ovaries
Fallopian tube
Q3. How do Homologous organs differ from Analogous organs?
Q4.A) What is the advantage of disposal paper cup over a plastic cup?
B) Why is reuse of materials better than recycling in saving our environment?
Q5. What is the significance of Fertilisation in flowering plants?
Q6. What is the necessity of judicious use of Coal and Petroleum?
Q7.Given below is the part of periodic table.
Li
Be
B
C
N
Na
Mg
Al
Si
P
As we move horizontally from left to right, what happens?
a)
b)
c)
O
S
F
Cl
To the metallic character of elements.
To the atomic size of the elements.
To the valency of the elements.
Q8. Give two reasons for avoiding frequent pregnancies in women.What are the methods of Contraception ?
a)Barrier method
b) Chemical method
c) Surgical method
Q9. What is Sex Chromosome? Mention the sex chromosomes present in male and female human.
Q10. A) What is meant by Budding?
B) Explain the reproduction in Hydra by Budding.
ANSWERS
Ans 1.The fine particles present in atmosphere scatter mainly blue component of
sunlight more strongly than red component of sunlight.So , colour of sky appers blue.
In the absence of earth’s atmosphere, there would not be any scattering,so,sky
would have appear dark.
Ans 2.a)The functions of Testes arei)to produce sperms
ii)to produce male sex hormone testosterone
b) The functions of ovaries are:
1) To produce female egg
2)To secrete female sex hormone
c)The function of fallopian tubes are:
1) to carry eggs from ovaries to uterus
2)to allow sperms to travel to meet the eggs
Ans 3.
Homologous organs
i)They have same origin and
structure but perform different
functions .
ii)The wings of birds are used for
flying and fore-arms of man are
used for holding things
Analogous organs
They have different origin and
structure but perform similar
function
Wings of birds and that of insects
look different but perform same
functions.
Ans 4. A)The disposable paper cups are biodegradable ,whereas plastic cups are non
Biodegradable.
B) Reuse of material is better than recycling in saving our environment
because reuse of material donot use any energy whereas recycling uses
some energy.
Ans 5.i) The entry of sperm activates the ovum.
ii) After fertilization ,a membrane is formed around the zygote which do not
allow any other sperm to enter.
iii) Fertilization restores the number of chromosomes.
iv) It brings two different lines of heredity together.
v)It brings variation in the offsprings.
Ans 6.The fossil fuels like coal and petroleum get exhausted and can not be
reproduced again.They produce harmful gases and oxides which are poisonous and
pollute the environment.
Ans 7. A)Metallic character decreases as atomic size decreases so tendency to lose
electron decreases.
B) Atomic size decreases as number of shells remain samebut effective nuclear
charge increases.
C)Valency first increases and then decreases.
Ans8.i) Affect health of woman.
ii) Increases population.
Methods of Contraception
a)Barrier method
b) Chemical method
c) Surgical method
Ans 9. Sex chromosomes are the chromosomes that operates in the sex determining
mechanism of species.
In male – XY
In female – XX
Ans 10.A) Budding is an asexual method of reproduction. In this method a bud like
structure grows out of the parent body and then detaches and become new organism.
B) Hydra reproduces by budding using the regenerative cells. A bud is
developed and then detaches when it is fully matured and develops in new individual.