BECE Past Questions & Answers – 2011 (SCIENCE)

INTEGRATEDSCIENCE2

SOLUTIONS

ESSAY

1. (a) (i) Light rays from the lighted bulb

(ii) Sees no light or a portion of card board B

(iii) Since light moves in a straight line, the observer sees the light only when the holes are in a straight line with the light source. Since light rays cannot bend around the card board B when slightly displaced, the observer does not seethe light

(iv) The observer would seethe light rays from the lighted bulb again.

(v) The property that light travels in a straight line or rectilinear propagation of light

(vi) (α)

Eclipse of the sun (solar eclipse) Eclipse of the moon (lunar eclipse) Day and night
Shadow [anytwo]

(β) camera, microscope, telescope, binoculars, periscope, torch, [anyone]

(b) (i) A – highly inflammable or flammable
B – Irritant or can cause harm
C – Poisonous or toxic or deadly
D – Dangerahead

(ii)
A
– liquefied petroleumgas(LPG), petrol, kerosene,spirit, ethanol [anyone]

B
– Concentrated Hydrochloric acid [Conc. HCl], concentrated sulphuric
acid [conc. H2SO4], concentrated magnesiumhydroxide [Mg(OH)2], concentrated sodium hydroxide [NaOH] [anyone]

C – Dichlorodiphenyltrichloroethane (DDT)[C14H9Cl5],Potassium cyanide
[KCN],Sodiumcyanide[NaCN], mercury [anyone]

(iii) On roads,at construction sites, very high voltage plants/devices, [anyone]

(iv) – They help prevent accidents by making people take precautions.
– They serve as warnings to prevent injuries or death.

(c) (i) A B C – incisor
– premolar / molar
– canine

(ii)
A B C
– chisel shaped
– almost flat surface with small projections / cusps /ridges
– pointed

(iii)
A B C
– Biting or cutting
– chewing or grinding or mashing
– tearing

(iv)
I II
– enamel / crown
– root

(d)
(i)
A B C D E
– Gardenfork
– Spade
– hand trowel
– hand fork
– wateringcan

(ii)
A
– Breaking up soil or making soil loose or ploughing soil or turning over soil

B
– Collecting soil or mixing substance such as animal feed or digging groundormakingsurfaceofgroundlevel

C
– earthing up crops or transplanting seedlings or spreading fertilizer or
manuring or mounding certain crops

D
– Breaking up soil or making soil loose or ploughing soil or turning over soil

E
– Wateringsoil /crops

2. (a) (i) Ruminants arecud-chewinghoofed mammals with multiple-chambered stomach.

(ii) Examples: camel,goat, sheep,giraffe, cow

(b) (i) A forceisapush or pullexerted on abody.
Or:

(ii) A physical influence that tends to change the position or shape of an object with mass

Effects of forces ona body:
• Can cause a moving body to cometo rest (stop moving)
• Can cause a body at rest to move
• Can cause a moving body to accelerate
• Can cause a moving body to decelerate
• Can change the direction of a moving body
• Can changethe shapeofabody [anytwo]

(c) (i) Ways of maintaining the carbon cycle:
• Afforestation (planting new trees to replace the ones that have been destroyed or cut down)
• Photosynthesis
• Respiration
• Reducing the amount of carbon dioxide emissions from industries
• Avoiding excessive bushburning
• Reducing the amount of fumes from vehicles [anytwo]

(ii) Environmental effects
• Global warming as a result of the depletion of the ozone layer
• Increase in volume of sea water due to melting of ice bergs
• Green house effect [anyone]

(d) (i) Protons, neutrons and electrons

(ii) PARTICLE RELATIVE CHARGE
Proton positive(+1)
Neutron no charge or neutral (0)
Electron negative(– 1)

(iii)
cation

3. (a) (i) A mixture is
A physical combination of two or more substances
Or:
A substance consisting of two or more substances that have been combined physically

(ii)
Why some mixtures are thoroughly stirred before they are used:

To attain a uniform mixture or to make it homogenous, since the original mixture may
not be uniform or there may be some suspended particles of the solute

(b)

(i)

Reflection of light is
The bouncing back or redirection of light when it strikes a surface

(ii)
Characteristics of images formed by plane mirrors:
 Same size as object
 Same distance from mirror as object
 Virtual
 Erect /upright
 Laterally inverted [any two]

(c)
(i)
A fertilizer is:

Any substance usually added to or spread onto soil to increase its ability to support plant
growth
Or: A substance added to soil to increase its nutrient content or fertility

(ii)

Examples of in organic fertilizer:

NPK or ammonium sulphate or urea or potassium chloride (or muriate of potash)

(d)

(i)

Indiscriminate sex
Having sexual inter course with multiple (two or more) partners and usually without
protection (use of condom)

(ii)
Dangers of indiscriminate sex
 Contracting sexually transmitted diseases (STDs),such as AIDS, syphilis, etc
 Teenage pregnancy(where teenagers are involved)
 Abortion, which is usually quit and dangerous to the mother
 Loss of social respect /reputation
 Loss of self-esteem [any two]

4. (a) (i) A simple machine

A mechanical device that makes work easier and/ or faster

(ii)
Examples of simple machines
Bottle opener, wheel barrow, nut cracker, inclined plane, spanner, crowbar, etc

(b)
(i)
Rusting is
the corrosion (wearing away) of the surface of iron or steel due to the formation of iron
oxide
or: the formation of a red dish brown coating of iron oxide on the surface of iron or steel that forms when the metal is exposed to air and moisture

(ii)

Effects of rusting:
• Shortage of life span of item
• Loss of beauty of item
• Reduction in effectiveness of implement
• Collapse of buildings [any two]

(c)
(i)
Food nutrients

Chemical substances, found in food, that the body needs in order to function properly

(ii)

CARBOHYDRATE FATS AND OILS PROTEIN
Bread palm fruits beans
Maize margarine meat

(d)
(i)
Effects of malnutrition in farm animals
 Deficiency diseases
 Stunted growth
 Low energy and activity(lack of vitality)
 Slow recovery from illnesses
 Death
 Lower reproduction [any two]

(ii)
Disease caused by virus
 Rabies
 Bird flu

 Newcastle
 Rinder pest [anyone]

5. (a) (i) Soil erosion:
The washing away of the top soil by agents of erosion
Or: The removal of soil material by natural processes,principally running water, glaciers, waves, and wind

(ii) Methods of controlling soil erosion:
• Planting of cover crops
• Planting of grasses
• Planting of wind brakes (trees)
• Ploughing across slopes
• Terracing
• Strip cropping [any two]

(b) (i) (α) Adaptation:
The development of physical and behavioral characteristics that allow organisms
to survive and reproduce in their habitats

(β) Endangered species
Species threatened by extinction:
Or: Species whose numbers are so few, or are declining so quickly, that the animal, plant, or other organism may soon become extinct

(c)

(i)

Example of hard water
Deep well water
Bore hole water

(ii)
It is advisable to drink hard water because
it contains dissolved mineral salts, such as calcium and magnesium salts, which are
necessary to maintain good health and proper functioning of the body.

NB: (Minerals are essential for the healthy growth of teeth and bones. They also help in
cellular activities, such as enzyme action, muscle contraction, nerve reaction, and blood
clotting)

(d)
(i)
Magnetic field:
A region of space surrounding a magnet or current-carrying circuit in which the resulting
magnetic force can be detected

(ii)
Methods of making magnets

 Electrical method
 Single stroking
 Double stroking
 Induction
 Hammering [any two]

6. (a) (i)

(α) Solvent:
A substance that dissolves things:
Or: A substance in which other substances are dissolved, usually a liquid

(β) Solute
A substance that is dissolved in another substance

(ii) Common solvent used in home
Water,Turpentine, liquid soap, alcohol, kerosene [anyone]

(b)
(i)
Ration:
A fixed and limited amount of feed,given to an animal or group of animals at specific
times / intervals.
This is done to ensure that the animal has the right amounts of essential food nutrients for
healthy growth and development.

(ii)
Dehorning:
Removing or preventing the growth of the horns of an animal by surgery or cauterization.
This is done primarily to prevent animals from using them to injure other animals or
destroy property

(c)
(i)
Element:
A substance that is made up of the same kind of atoms
Or:
Any substance that cannot be broken down into a simpler one by a chemical reaction

(ii)
(α) Potassium – K
(β) Sulphur – S

(d)
(i)
Mixed farming:
The cultivation of crops and the rearing of livestock on the same farm at the same time
Or: farming that combines growing crops and rearing livestock on the same farm at
the same time

(ii)
Mixed cropping
The cultivation of different kinds of crops on the same piece of land at the same time