KNEC KCPE SCIENCE 2018 PAST PAPER AND ANSWERS

KNEC KCPE SCIENCE 2018 PAST PAPER AND ANSWERS

INSTRUCTIONS TO CANDIDATES (Please read these instructions carefully)

1. You have been given this question booklet and a separate answer sheet. The question booklet contains 50 questions.
2. Do any necessary rough work in this booklet.
3. When you have chosen your answer, mark it on the ANSWER SHEET, not in this question booklet. HOW TO USE THE ANSWER SHEET
4. Use an ordinary pencil only.
5. Confirm that the answer sheet that you have been provided with has the following:
   YOUR INDEX NUMBER
   YOUR NAME
   NAME OF YOUR SCHOOL
6. Do not make any marks outside the boxes.
7. Keep the sheet as clean as possible and do not fold it.
8. For each of the questions 1—50, four answers are given. The answers are lettered A, B, C and D. In each case only ONE of the four answers is correct. Choose the correct answer.
9. On the answer sheet, show the correct answer by drawing a dark line inside the box in which the letter you have chosen is written. ​

This Question Paper consists of 7 printed pages and 1 blank page.

Question 1.

The form of energy that comes second during energy transformation in a torch which uses dry cells is:
   A. light.
   B. electrical.
   C. chemical.
   D. heat. 

ANSWER

The answer is: B. electrical
Reason:
The 1. chemical energy stored in batteries gets transformed into 2, electrical energy through the wires. This then gets transformed into 3. light energy that you see.

Question 2.

When rays of light pass from air to water they
   A. bounce back.
   B. increase in size.
   C. are bent.
   D. are absorbed. 

ANSWER

The answer is:    C. are bent.

​When light rays travel from air into glass or from air into water, it bends towards normal. This is because the speed of light rays decrease while travelling from air into glass or water.

Question 3.

In which one of the circuits below would the bulb light? 

ANSWER

The answer is C.

Reason:

1. ​the batteries are arranged in series form
2. positive charge is connected to electrical foot contact
3. negative charge is connected to base contact wire

Question 4.

The purpose of each of the following is insulation against heat loss EXCEPT 
  A. clay pots. 
  B. wooden handle frying pan. 
  C. woollen clothing. 
  D. window curtains. 

Answer

D. window curtains. ​

window curtains are used for decoration,  security and privacy.

Question 5.

A plane mirror is placed at the beginning of the word MALARIA. Which one of the following groups of letters will remain the same when the word is reflected?
   A. M,A,L.
   B. M,A,I.    
   C. R,A,I.
   D. L,I,A.

ANSWER

B. M,A,I.

AIЯA AM

Question 6.

Which one of the following pairs of materials are correctly matched with the heat transfer processes that take place in them?
  Convection    Radiation
   A. Water           Vacuum
   B. Air                 Iron rod
   C. Glass            Water
   D. Vacuum       Air 

ANSWER

  Convection    Radiation
   A. Water           Vacuum

• Heat transfer through vacuum occurs in form of packet of energy like electromagnetic waves spectra, not being affected by medium through which it travels. Mode of heat transfer, well known as Radiation.
  
• Convection is heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it. Convection above a hot surface 
  
  occurs because hot air expands, becomes less dense, and rises
  
  

Question 7.

Which one of the following pairs of substances is correctly grouped according to its characteristics? 

	Definite Volume	No Definite Shape
A.	Air	Water
B.	Stone	Kerosene
C.	Cooking Oil	Wood
D.	Bottle	Book

Answer

	Definite Volume	No Definite Shape
B.	Stone	Kerosene

Reason:

• Solids have a clearly stated volume, and a stone is a solid
• Kerosene is a liquid and all liquids have no clearly stated shape. 

Question 8.

In an experiment on mixing of liquids. water, cooking oil, fresh milk and kerosene were mixed two at a time. Cooking oil mixed well with
   A. water and fresh milk.
   B. water only.
   C. fresh milk and kerosene.
   D. kerosene only. 

Answer

   D. kerosene only. ​

kerosene is miscible with cooking oil because their mixture is a homogeneous solution

Question 9.

A component of air used for germination is also required for
   A. burning substances.
   B. preserving soft drinks.
   C. making proteins.
   D. making electric bulbs. 

ANSWER

   A. burning substances. 
the component of air that supports germination is oxygen. Oxygen supports burning of objects also

Question 10.

A mixture of sand, salt and husks can be separated by
   A. dissolving, filtering and winnowing.
   B. winnowing, dissolving, filtering and evaporating.
   C. dissolving, filtering and evaporating.
   D. picking. sieving, dissolving and filtering. 

ANSWER

   B. winnowing, dissolving, filtering and evaporating.
Reason:

• winnowing removes husks
• dissolving dissolves salt in water so that we can filter sand
  
• filtering gets rid of sand
  
• ​evaporating gets rid of water so that we can remain with salt.
  

Question 11.

The diagram below shows parts of a flower.

​Pupils made the following statements about the parts labelled W, X. Y and Z. 
(i) W produces nectar.
(ii) X produces pollen. 
(iii) V transfers pollen. 
(iv) Z allows pollen tube to germinate. 
Which two statements are correct? 
   A. i and ii
   B. ii and iv
   C. iii and iv
   D. i and iii

answer

   B. ii and iv
Reason:

• Petal (W)- attract insects which are very important in transfer of pollen
• Anther (X) - produces male gametes (pollen) 
• Stigma (Z)- it is a sticky landing area for pollen before moving to the ovary
• Filament (Y)- ​supports anther to make it accessible to insects

Question 12.

​The following features were observed on some plants: 
(i) deep roots. 
(ii) broad leaves. 
(iii) numerous stomata. 
(iv) thorns. 
Which two features are for plants found in dry areas? 
   A. (i) and (ii). 
   B. (ii) and (iii 
   C. (iii) and (iv). 
   D. (i) and (iv). 

answer

   D. (i) and (iv). ​
Reason:

• Desert plants are deep rooted so that they can reach water
• Desert plants have thorns to repulse herbivores from feeding on them.
• The surface of their leaves is waxy to reduce evaporation of water
• Their leaves are tiny to reduce evaporation and reduced manufacture of food due to scarcity of resources.
• They occupy small surface area to reduce precipitation
• Some such as cacti are succulent because they are adapted to storage of water.

Question 13.

​Which one of the following is a field pest? 
   A. Weevils. 
   B. Aphids. 
   C. White ants. 
   D. Rodents. 

ANSWER

Field pests are pests that destroy live plants such as leaves, stems and roots as opposed to storage pests that destroy grains or dead plants.
​Answer:
​   B. Aphids. 

Question 14.

​Which one of the following is NOT a condition for germination? 
   A. Soil. 
   B. Oxygen. 
   C. Moisture. 
   D. Warmth. 

answer

   A. Soil. ​
Soil is never a condition that is required in germination. What is important is oxygen, moisture and warmth

Question 15.

​The following are ways through which plants show interdependence EXCEPT 
   A. sharing food. 
   B. support. 
   C. provision of shelter. 
   D. provision of medicines.

answer

   D. provision of medicines.

Question 16.

​Which one of the following characteristic is found in reptiles but NOT in birds? 
   A. A back bone. 
   B. Scales. 
   C. Lungs. 
   D. Varying body temperature. 

answer

   D. Varying body temperature. 
​reptiles are cold blooded animals, birds are not.

Question 17.

​Which one of the following methods of controlling livestock parasites will control both roundworms and ticks? 
   A. Dipping. 
   B. Rotational grazing. 
   C. Spraying. 
   D. Clearing vegetation. 

answers

   B. Rotational grazing.

• Pasture rotation and paddock resting will help to break the cycle of both the roundworm and a tick.

Question 18.

The diagram below shows a bird’s beak.

​The bird is likely to be a 
   A. grain eater. 
   B. filter feeder. 
   C. flesh eater. 
   D. nectar feeder. 

answer

   D. nectar feeder
Reason:
Beak is sharp pointed

Question 19.

​The following are some parts of the human digestive system: 
(i) oesophagus. 
(ii) stomach. 
(iii) small intestines. 
(iv) large intestines. 
In which two parts does digestion of food take place? 
   A. (i) and (ii). 
   B. (ii) and (iii). 
   C. (iii) and (iv). 
   D. (i) and (iv). 

answer

   B. (ii) and (iii). ​

Question 20.

​Which one of the following parts of the breathing system warms the incoming air? 
   A. Nose. 
   B. Trachea. 
   C. Diaphragm. 
   D. Lung. 

answer

   A. Nose. ​
​At the top of the respiratory system, the nostrils (also called nares) act as the air intake, bringing air into the nose, where it's warmed and humidified.

Question 21.

​Which one of the following changes occurs in both adolescent boys and girls? 
   A. Production of sex cells. 
   B. Hips broaden. 
   C. Voice breaks. 
   D. Enlargement of breasts. 

answer

   A. Production of sex cells. ​

wet dreams for boys and menstruation for girls symbolizes production of sex cells

Question 22.

​A human zygote is formed in the
   A. vagina.
   B. cervix.
   C. uterus.
   D. oviduct. 

answer

C. uterus.
​Fertilization occurs within the female's uterine tubes, usually within 24 hours after ovulation. By that time, the oocyte has traveled a few centimeters down the uterine tube towards the uterus, while the sperm have made the long trek from the vagina, through the uterus and into the uterine tube forming a zygote.

Question 23.

Which one of the following blood vessels carries blood from the left ventricle?
   A. Vena cava.
   B. Pulmonary artery.
   C. Aorta.
   D. Pulmonary vein. 

ANSWER

   B. Pulmonary artery.
The pulmonary artery channels oxygen-poor blood from the right ventricle into the lungs, where oxygen enters the bloodstream.​

Question 24.

Use of cover crops for conservation of soil will work in the same way as
   A. planting of trees.
   B. mulching.
   C. terracing.
   D. contour farming. 

ANSWER

   B. mulching.
growing of cover crops helps prevent soil erosion and losing of water from the ground through evaporation so does mulching

Question 25.

The following are observations made on fertilisers and manures:
(i) nutrients are readily released.
(ii) have nutrients in specific amounts.
(iii) improves soil structure.
(iv) benefits are long term.
Which two observations are for manure?
   A. (i) and (ii).
   B. (ii) and (iii).
   C. (iii) and (iv).
   D. (i) and (iv). 

answer

   C. (iii) and (iv).

1. Using manure improves the soil structure (aggregation), so that it holds more nutrients and water, and makes the soil more fertile. 
2. Manure encourages soil microbial activity that promotes the soil's trace mineral supply, improving plant nutrition. It also contains some nitrogen and other nutrients itself which assist the growth of plants. 
3. As it is an organic product, it will not cause any harm to the environment.​

Question 26.

​Which one of the following activities could cause a reduction in the number of animals in a river? 
   A. Washing vehicles in the river.
   B. Dumping human waste into the river. 
   C. Wild animals watering in the rivers. 
   D. Cutting trees from the river bank. 

answer

A

Question 27.

​Which one of the following consists only of living components of the environment? 
   A. soil, water, fern. 
   B. water. wind, mushroom. 
   C.mushroom, fern, moss. 
   D. moss, wind, soil. 

answer

C

Question 28.

​Which one of the following will increase the rate at which soil is carried away by running water? 
   A. Planting sweet potatoes. 
   B. Terracing the farm. 
   C. Cultivating along the slope. 
   D. Strip cropping. 

answer

C

Question 29.

​The diagram below shows a simple machine with positions labelled E. F, G and H.

​For the machine to make work easier the effort should be applied at point 
   A. E. 
   B. F.
   C. G. 
   D. H. 

answer

C

Question 30.

​The machine used to raise a flag makes work easier by 
   A. changing the direction of the effort. 
   B. making the load lighter. 
   C. reducing the distance that effort moves. 
   D. reducing the effort. 

answer

A

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