1979-11-21 — Page 31

育教僑華 真三第張八第

日二初月十年未己曆夏

1980

中學會考試題預習專欄

生物(七)

明德出版社梁永華提供資料

Biology (7)

Ww. Leung

(Mill & Dale Press LUG

Tuit 5: Transport in organisms

The following diagram shows

general plan of blood

circulation în mamma 1

LIVER

INTESTINE

KIDNEY

(a) Explain why the blood

in the circuit

(1) can flow constantly, (2) can flow forward

without back-flow (b)(1). Name the chamber Y (2) When chamber X

contracts, to which organ is the blood in it sent? Explain why the wall of chamber Y is thicker than that of chamber X.

What are the difference's in the composition of the blood in

(1) chamber X and

chamber Y?

hlood vessel A and

blood vessel B after a diet:

blood vessel C and.

1980

中學會考試題預習專欄

地理

(+)

明德出版社李婉儀提供資料 Geography (7)

Questions for Revision;

Below is a photograph

taken on Cheung Chau Island, Hong Kong. The features -shown on the photo resemble

a certain landscape found in limestone area.

Name the type of land- scape that is found. in limestone area and explain its formation. on what type of rock do you think features of similar appearance may develop in Hong Kong. Give a reasoned account of it.

Suggested Answers:

In the limestone regions such a type of landscape is known as Korreu land- scape, which is marked by deep, and narrow grooves separated by round or flat

topped ridges. The deep

and narrow grooves are: often produced by solution

1·4

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Di deoxygenated

blood, with little urea.

Alnad vessel DZ

(d) Name "blond vessel A slate its function, (e) Nume two hormones which

speed up the circulation. The following diagram shows. a vertical section of the he:

Right ventricle

Pulmonary

artery

Left Ventricle

(1) Name the

structure (2) What is it's

function?

(1) Name tlie

structure: 3. (2) What is its

function?

Why should the aorta have a thicker wall than the pulmonary artery?

(d) What are the

double-circulation in

manmal's?

(e) what are the advantages.

of having a Tour Four-chambered heart?

(†) Why does exercise

changes the heart rate? (B) State two situations

at which the heart rate

along joints since joints in limestones are generally well-developed

the rock, which is made up of calcium carbonate, is

easily dissolved in dilute carbonic acid former when

rain water absorbs carbon

dioxide, as it falls through. the atmosphere. The joints are thus gradually opened up or widened as rain-water

seeps through them. Grooves, which are known as grikes, are therefore resulted. They are separated by the flat or round-topped ridges called clints.

limestone is absent in Hong Kong and therefore we cannot see at first hand- the results. However, similar features can be found on granitic areas,

..

on Cheung Chau Island. It is because granite is also a kind of well-jointed. rock on the rock where parallel joints are well developed, rain-water, humid air or salt spray from the sea will remove the soluble material such as feldspar along the joints. Weathering which concentrates along joints. gradually enlarges them and deep, and narrow grooves. resulted. They are found separated by the remaining parts which look like flat topped ridges. Such a type of landscape on granite is known as 'seudo-Karren

**

Landslides are very common in Hong Kong, Give an account of

all

the factors. responsible for their

some

occurrence, and enggest possible ways to prevent

thew

Suggested Answers:

CAUSES OF LANDSLIDES IN IEK.

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is decreased.

(a) What is the difference

between blood capillary. and lymph capi

(b) (1) State two functions

of tissue fluid,

nswer:

(2) Describe tvo

differences between tissue fluid and blood.

(3) How does the tissue.

fluid get linked up with the blood?

Describe how the following items present in the blood give us protection::

(1) white blood cells, (2) salts,.

(3) clotting of blood.

The rhythmic pumping. action of the heart keeps the blood in the circuit to flow constantly.

The blood in the circuit can flow forward because

the pumping action of heart gets up a blood pressure which forces the blood to flow forward, and

there are valves in the heart and veins to prevent the back back-flow of blood.

(b) (1) Right ventricle.

(2) The lungs.

(3) It is because the wall of chamber Y has to pump blood to distant organs from the beart,

X. deoxygenated

blood,

Y. oxygenated blood,

A rich in nutrient, B1 rich in urea.

(3) C: oxygenated blood, with ures, Landslides are very common in Hong Kong, especially in the rainy summer months. The factors responsible for their occurrerce are;

Types of Rocks:

Granite is a common rock in Hong Kong and it is easily subjected to weathering, , especially under the moist and warm climate which encourages active chemical weathering. Thick layers of weathered materials are usually found found on slopes The weathered mantle may have a depth of 200 feet. These Foosened materials are very likely to slide down steep slopes whenever there is a change in the environmental factors e.g. heavy rainfall removal of support or weight added above. In some cases, landslides take place where the uore resistant volcanic rocks overlying weathered granite. In these cases, landslides happen by undercutting, i.e. the weathered granite is removed first leaving the volcanic rock to slump down.

2/ Climate

The uneven distribu- tion of rainfall is also. an important contributing factor. From May to September, Hong Kong may be affected by stationary trough which may bring continuous and intensive rainfall. The record of 375 500mm a day is not surprising, The water soaks into the ground and may act as a lubricant or destroy the cohesiveness of soil. All these render the slope unstable. More- over, the heavy rainwater may add weight to the

(d) Repatic portal.

vein.

It transports the

digested products from The intestine to the liver.

Adrenaline and thyroxine,

(1) A tricuspid valve. (2) A prevents the

(~) (2)

backflow of blood. from right ventricle to right auricle. when right ventricle

contracts.

B: heart stringa. Wholds cuspid

valves in closed position when

ventricle contracts.

(c) The aorta has to resist

higher -blood pressure.

(d) 1. pulmonary

circulation,

2. body circulation, (e) It permits a complete separation of the oxygenated blood from the deoxygenated blood. so there is a rither supply of oxygen to the tissues. Also, the heart pumps the I

blood twice so a high blood pressure is developed to permit a rapid transport of substances throughout the body.

An increase in muscle. actions means a rise in the requirements of oxygen and glucose, and the rapid removal of extra carbon dioxide. and metabolic wastes such as lactic acid. The heart responds by pumping blood round the body faster..

sleep,

slope and make the whole mase become more susceptible to downslope movement. Structural Condition

The hilly nature of Hong Kong is also a favourable factor. The abundance of steep glopes provides an ideal. condition for thë occur- rence of landslides.

4/ Vegetation Cover

Since it has been believed that vegetation can provide a

a protective cover, the scarcity of binding vegetation cover isconsidered as a contributing factor, too

5/ Human Activities

* Due to the rapid increase of population and the limited supply of flat land, high buildings have been constructed on hill-slopes. It is already. accepted that the existing. natural hillside slopes, where made up of colluvial material, are in a state of limiting equilibrium, since they are not the final slopes of these. hillsides. Excavation or cutting of those slopes automatically increases the slope angle and this increases the risk of landslips.

PREVENTIVE MEASURES

In an attempt to prevent landslides the following ways are suggested:

1: The Government should limit intensive deve lopment of those mid- level areas where, the soi soil is of colluvial origin and the hillside slopes are in excess of 35

2. The Government should immediately review its current land policy with

advancing age.

Blood capillaries form

dense network for

linking an artery and

vein, while lymph capillaries are composed of blind ducts and normally largers than blood capillaries,

(8) (1)

as

medium for gaseous exchange between blood capillaries and tissue cells, as a medium for the exchange of nutrients and metabolic waste products.

(2) Tissue fluid containa.

no red blood cells" and blood platelets. (3) Lymph capillaries

unite to form larger vessels which finally collect into the thoracic duct and the right lymphatic. The latters connect with two veins which lead into the superior

vena cava.

(c) (1) White blood cells can kill invading agents by engulfing them or by secreting antibodies and promote blood clotting and tissue repair.

(2) Salts contribute to

osmotic pressure, to form buffer systems. (3) clotting of blood

prevents further bleeding and contamination by foreign agents.

a view to decentralizing the urban areas and utilizing some of the flat land in the New Territories for this purpose. This is to be preferred to further exploitation of hilły. terrain involving large scale cuttings and

excavations.

3: More carefully survey

should be done before construction,

: Surface drainage

channels or conduits can be constructed to. drain the water on the slope. In all ground susceptible to soil creep, water service mains," particularly those carrying water under high pressure, should be constructed of materials which are not of a brittle nature and thus particularly liable to fracture arising from differential movement the soil.

5: The Laying of a lay

of 'Chunam' plaster or cement on the surface of cutting is also effective în preventing large quantity of

the

slope

seeping Seton

6: As some

preliminary movements probably take place before the rock Bass breaks loose, suspected slopes should be detected oftenly. Both the Resettlement and the Public Works Department should continue to act on complaints about possible dangers in existing squatter areas, In addition, regular inspec- tions of these areas should be made by experienced engineers to, watch out for possible danger spots and to take action when necessary to alleviate such danger.

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