VIII SCIENCE

1.       Organic nutrients are called

(a)Fertilizers       (b) Manures       (c) Both a) and (b)           (d) None of these

2.       For safe storage of cereal grains, moisture content of the grain should not be more than

(a)84%                  (b)44%                  (c) 34%                                 (d) 14%

3.       Pasteurization of milk destroys its

(a)vitamins                         (b)fat contents (c) bacteria                         (d) None of these

4.       Carrier of malaria causing pathogen is

(a)House fly       (b)Cockroach     (c)Female Anophleses                   (d) None of these

5.       The raw material used for Teflon is

(a)ethene           (b)wood pulp    (c)ester                                (d)tetrafluoroethene

6.       The process by which artificial fibers are made is called

(a)Polymerisation            (b)plasticity        (c)elasticity                         (d)regeneration

7.       A superior synthetic fibre made by the polymerization of amide molecules obtained from petroleum is called:

(a)teflon              (b)nylon               (c) koroseal                        (d)rayon

8.       Which one of the following is a non-metal and good conductor of electricity

(a) zinc                  (b)lead (c) graphite                         (d)lithium

9.       Which among the following is not a noble gas

(a)helium                            (b)neon               (c)bromine                         (d)argon

10.   Which among the following is used in for making microchip for electronic goods

(a)sodium                           (b)sulpher           (c)silicon                              (d)phosphorus

11.   Which among the following is not a component of biodiversity?

(a)plant                                (b)animal             (c)microorganism                             (d)water

12.   Species which are restricted to a particular geographical region are called:

(a)endangered species (b)vulnerable species (c)endemic species  (d)wildlife

Sperms are produced by

(a)ovary (b)oviduct (c)testis  (d)uterus

13.   Which among the following is not a component of female sex organ?

  (a)uterus (b)oviduct (c)testis  (d)vagina

14.   Which among these is not a oviparous animal

(a)lizard (b)frog (c)lizard  (d)rat

15.   A car is heading towards south-east. The force of friction acting on the car is towards

(a)south-east (b)south-west (c)north-east  (d)north-west

16.   A cubical body has surfaces 5cm2, 20cm2,10cm2. Which surface will offer maximum frictional force

 (a)20 cm2 (b)10cm2 (c)5cm2  (d) all will offers same frictional force

17.   1kgf is equal to

(a)10 N (b)100 N (c)1000N  (d)none of these

18.   The force which exists between an electrically charged body and an uncharged body is:

(a)    electromotive force(b)electrostatic force (c)biological force  (d)magnetic force

19.   The practice of leaving the field uncultivated is called

20.   What are the two main crop seasons? Give three example of the crops grown during each season.

21.   What is crop rotation? Mention its advantages.

22.   Two diseases each caused by bacteria , fungi, protozoa and virus.

23.   What is vacnine? Who developed the first vaccine? How does it prevent us from the disease?

24.   What beneficial role do microorganism play in the life of human beings?

VACCINATION

What is a vaccination and how does it work?

Vaccinations protect you from specific diseases that can make you very sick, disable or even kill you. They boost your body's own defence system, which is also called the immune system.
Vaccines create immunity that protects you from an infection without causing the suffering of the disease itself.  Sometimes vaccines are called immunizations, needles or shots.
Here's how vaccines work:

• Most vaccines contain a little bit of a disease germ that is weak or dead. Vaccines do NOT contain the type of germ that makes you sick. Some vaccines do not contain any germs.
• Having this little bit of the germ inside your body makes your body's defence system build antibodies to fight off this kind of germ. Antibodies help trap and kill germs that could lead to disease.
• Your body can make antibodies in two ways: by getting the disease or by getting the vaccine. Getting the vaccine is a much safer way to make antibodies without having the suffering of the disease itself and the risk of becoming disabled or even dying.
• Antibodies stay with you for a long time. They remember how to fight off the germ. If the real germ that causes this disease (not the vaccine) enters your body in the future, your defence system knows how to fight it off.
• Often, your defence system will remember how to fight a germ for the rest of your life. Sometimes, your defence system needs a booster shot to remind it how to fight off this germ.

Sometimes vaccines prevent one disease. Sometimes they are combined to protect you from several diseases with one shot. For example, the MMR vaccine fights Measles, Mumps and Rubella (German measles).
Most vaccines given in Canada are by needle. Scientists are looking at new ways to give vaccines, such as by mouth or with nose spray.