MODEL EXAM (2) ANSWERS

Posts : 185 Join date : 2010-01-28

1 ^st Life Science :

1. State If the following sentences are true or false , then correct the wrong sentences :2 marks

1. Cartilaginous fish have jaws, scales, and skeleton made of cartilage. ( T )

…………………………………………………………………………………………………………

2. if the shark loses its front teeth, a tooth behind it moves to replace it, & so they are called Replacements. ( T )

…………………………………………………………………………………………………………

2. complete the following sentences: 4 marks

1. A larva is an immature form of an animal that looks very different from the adult.

2. Echinoderms are not hermaphrodites they are either male or female

3. Give the scientific reasons for the following: 2 marks

1. mammals are complex organisms

Because they are multicellular organisms with many complicated systems

4. What would happen if: 2 marks

1. the eggshell of a bird is like the reptile's eggshell

the eggs may be broken when they roll or the bird sit on them

5. Label the following drawings :2 marks

a) What kind of animals is this invertebrate?

A mollusk

6. Give the scientific term :2 marks

a kind of mammals that develops inside its mother's

body until its body systems can function independently. (placental mammal)

Internal system of fluid filled tubes in echinoderms.. (water vascular system)

7. Compare between the following (two items are needed for each): 2 marks

Closed circulatory system	Open circulatory system
The blood is always in the blood vessels Such as in worms	The blood is not always in the blood vessels Such as in mollusks

8. Answer the following questions : 2 marks

Which body form of cnidarians is reproducing sexually?

Medusa

what characteristics do fishes share with all other vertebrates?

Backbone(notochord), closed circulatory system, gill slits and nerve chord along the back

9. Choose the correct answer:2 marks

A ……………lives on or inside an organism.

a)Host b) free-living organism c)scavengers d)parasite

all mollusks are characterized by:

a)segmented body b) presence of shells. c)soft bodies. d) compound eyes

2 ^nd chemistry :

1. State If the following sentences are true or false , then correct the wrong sentences :2 marks

1. nitrogen molecule consists of 2 atoms ( T )

………………………………………………………………….………………………………..……

2. The coal burning is a slow combination with oxygen ( F )

…………………………………………fast……………….…..………………..…………………

2. complete the following sentences: 4 marks

1. Each element has a symbol may be one , two or three letters such as carbon C but Sodium is Na

2. the number of neutrons = mass number _ atomic number

3. Give the scientific reasons for the following: 2 marks

1. gases take the shape of the container

because their particles are far apart from each other and moving freely and randomly everywhere with very low intermolecular forces

4. What would happen if: 2 marks

1. brass combines with sulfur

it will form tarnishing

5. Label the following drawings :2 marks

a) Label 1, 2, 3 and 4 on the diagram

1. Heat

2. mixture (salt + water)

3. Condenser

b) What is the function of this instrument?

Separating salt from water and collecting water vapor

after condensation

6. Give the scientific term :2 marks

A change in which energy is released (exothermic change)
materials that can be hammered or rolled into flat sheets

and other sheets (malleable metals)

7. Compare between the following (two items are needed for each): 2 marks

mass	weight
The amount of matter an object has Does not change for an object from place to place at the same time	The amount of attraction toward Earth on an object Changes from place to place at the same time