1970-02-12 — Page 22

and (b) breathing are accomplished at the various stages of development.

頁二第張六第日七初月正年戌庚夏

WAH KIU YAT PO

報日僑華

四期星日二十月二年〇七九一曆公年九十五 剑民育教鴦華

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院主編

生物科(十五)

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中學入學試試題預習專欄

英文科

智慧出版社主編

(十五)

Answers to Previous Exercises

SECTION

I

1.D 2. B 3.-2 4. B 5. D

2. S 3. 3. 4. Q 5. S. SECTION B III: 1. Did the news cause great alarm? -

2. Do I sit for the Secondary School

Entrance Examination?

3. Are all mon equal in the sun? la Does he push me out of his room? 5. Bas Mary got any of her suns right?

atsemer did not strike the rock

2. You ought not to have worked hard, 3. Do not throw the rubbish away.

ka Tou does not leave the party without

zy porziɛsion."

5. Won't you go to tãs soo with me?.

(multiple stoics).

choose the right word for the sentenan by drawing.

fifa line across the correct box.

31land

ABC DE

C. forest

« place

D. mountain

covered with treas.

person who sells fish is called

D. M

2. Mou

ABCDE

A B C DR

and was

soda

There zra

yeara da a

A. Century.

ABCDE

fer imaging e oer is esatel

ABG DE

Woon you travel in a bus or a ferry, you are

A. parter.

A B C D E

B. visitor.

G. stranger.

D. villager.

I. passeng®2-

II.

Choose the correct answer and mark it by

drawing a fire line across tõe right ber,

Two pupils vore seated on

child:

4. such

8. a listle

2. littio

8. big

7. several

F. each

few

PORT

BIOLOGY (15)

answer to zas questions of last week

[1 Describe, with the aid of a well labelled diagram,

the external features of a frog. What mentioned features of the frog do you consider as the adaptation of the frog to its living environment.

Ans.

The body of a frog can be divided into three distinot region the head, the trunk and the limbs. A nook region is not evident and the tail is lost during embryonic development.

The head of a frog in broad and flattened.

A large mouth is located at the anterior and of the head and a pair of external nostrils is dorsal to the front of the mouth. The large and protruding eyes are protected by eyelids. The upper eyelid is a simple skin fold; the lower ona is a translucent. membrane. When the eyeball is retracted into the eye socket, the lower eyelid spreads over its surface. Around eardrum; or tympanic membrane, lies posterior to the exalt

The trunk of a frog is short and compact. The skin is dark green or dark brown and sliny without soalan.

The fore-limbs are much shorter than the hind-limba. Bach fore-limb onsists of threa parts: the upper arm, fore-ara, and the hand respectively. The hand has only four digits for the thumb is missing. The hind-limb consists of four parts, namely the thigh, shank ankle and foot, The foot has five toss, and toes are connected with each other by a membranous wab,

A cloacal aparture is located at the posterior end of the trunk. Through this opening. the faeces, urine and reproductive products are discharged.

Nostril

Eardrum

Mouth

-Fore-limb

Fingers

Toes

Hind-limb

Web

cloaca

The External Feature Of A Frog

The following characteristic features of a frog are usually considered as the adaptation of the frog to its living environment- (i) Ite colourful, s smooth, and moist skin servas for protection, sensory reception and for gases exchange between the animal and its:

environment.

(ii) The large mouth enables the frog to swallow

large prey as a whole.

(iii) The broad and wide head connected with a

stream-lined body for easy movement in water

(iv) The powerful and large hind-limba are adapted

for leaping, twimming and for escaping from its enemies.

(v) The short and strong fore-limbs hold up tha

body when the frog rests on land.

(vi) The membranous webs present in the feet for

easy swim in water.

(vii) The cloacal aperture provides a passage for the

waste products and reproductive, matters tó pass through.

Outline the changes that occur during the

evelopment of a newly hatched tadpole into an adult frog. Indicate briefly, how (a) feeding,

PQ2ST

R. Every

reach the

S. Kuch.

PQRST

Leap year falls in 2. little rourth 2.00boo

3. mary

one hundred year

ACTIONS

II. 1111 in the blank spass with the correst form

of the word given on the left:

11ht:

Ans. The changes from a newly formed tadpole to

adult frog are summarized as followss

The larval stage: tadpole

About two weeks after fertilization, the

embryo wriggles out of its jelly oapsule and batches into a free-swimming larva, the tadpole. Nasal cavities, finger-like external gills, mouth and cloacal opening soon appear. The intestine is straight at first, and then coiled like a watch spring. At this stage, the tadpole attaches itself onto the jelly capsule firet by U-shaped sucker, and later clings to water weeds, About 3 to 6 weeks after hatching, the external gills are gradually absorbed and replaced by four internal gills that develop within the gill slits. The gills are covered b a fold known as the operculum, with only one epiracle on the left side of the head. At this stage, the sucker disappears. Two small projections appear at the either side of the base of the tail which will gradually develop into the two hind-limbs, The two fore-limbs develop almost at the same time.

When the tadpole is about two monthe ong

the

horny jaws are discarded and the mouth widens, At. the same time, the intestine becomes shorter, the lungs begin to develop and the internal gills gradually degenerate,

Metamorphosiss

After two to three months, the young frog undergoes a metamorphosie, a period of rapid differentiation during which larval features are lost and those of the adult are acquired. The tail is resorbed. The head changes into broad and vide, a tongue develops in the mouth. A tympanie membrane and eyelids appear, and even the shape of the lens changes to provide for good viaion in air, which has a different refractive index. Finally gonads develop and differentiate into tastes or ovaries.

idult stage: Frog:

The young frog will grow in size and attaing] its sexual maturity in the third year, (a) and (b):

Periods

A newly hatched tadpole

A "tadpole

with ex gills

A tadpo .with

internal gills

A young frog with

both fore-" limbs, and hind-limbi.

An adult Trog

Feeding

feeds on the yolk matter.

feeds on the

Breathing

Breathes in oxygen and [gets rid of carbon [dioxide through its

skin surface.

Respires by means of

plant materials, external gills.

euch algae

and vegetables d

in water,

AN

also depends on the plant ImaterialS. FOT

the food supply.

gradual changes

Respires by means of internal gille. At this stage, the respiration resembla closely to a fish doe

When the internal gilla to a carnivorous degenerate gradually, diet.

|the young frog breathes

by 'noase of skin and lungs

feeds on insects, breathes dissolved worms, shaila

and even the small frogs'.

Quastions for this week

joxygen in water and atmospherio six by means of skin, mouth and lunge.

What features in common have the insects you have studied? Name two insects which are pesta and describe the methods of control which are smployed against them, stating why augh' measures are necessary?"

(b) Write an essay on the economic importance of

insects.

(a) dive brief reasons for classifying a Cabbage

White Butterfly as (1) an invertebrate, (11); an arthropod, and (iii) an insect,

(b) Wish-sne nelp or diagrams, give an account of the life-history of a Cabbage White Butterfly.

conversation. Add correct punctuation the necessary word in capital letters,

what is that asked little John

this is a lisard replied pater it has four] legs and a long tall

and

does it hurt asked little John looking with interest no it doesnt bite people it runs quickly on the wall what does it live on

flies and mosquitoes answered, peter.

P. Mary

3. 1. Back.

5. A little

1. Every

thing.

P. Buch

All

Why are you in R. mush

f. big

PQRST

is a very

PORET

W.

A feather is

leaf.

David sits

in an armchair,

diligant:

This is the

pup in the aless.

tupidr

He was very ill yesterday but is

boday.

„Pigs are usually

than dogs.

Some Duzatuation marka sro minsed, in the followix