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[Abu mota]

Q.18 and Q.22 Summer 1999 Biology

 

[Abu mota]

also Oct/nov 1999 Q.18 and Q.37, i think there is something wrong with the MS, i think i did both of these questions and the answer for 18 was A and the answer for 37 was B, but imnt sure which papers. ty

 

[JOEJOE]

mj '99
Q-18 Ans = B.. coz the arrangement of the apparatus allowed co2 to leave but doesnt allow o2 to enter..
Q-22 Ans = C because the auxins will first be concentrated at the tip (A) and then diffuse down but away from the light so B and D are wrong because they are opposite to the direction of light where auxins will be so C is correct since it has lowest amount of auxins.

O/N '99
Q18 ans = B coz at A->B its constant (resting) after that it increases so he starts exercising at B
Q37 ans = D since when a limiting factor is introduced the population is either increasing or decreasing so B and C are wrong because they show a change and A is just wrong u cant have a constant environment

 

[Abu mota]

mj '99
Q-18 Ans = B.. coz the arrangement of the apparatus allowed co2 to leave but doesnt allow o2 to enter..
Q-22 Ans = C because the auxins will first be concentrated at the tip (A) and then diffuse down but away from the light so B and D are wrong because they are opposite to the direction of light where auxins will be so C is correct since it has lowest amount of auxins.

O/N '99
Q18 ans = B coz at A->B its constant (resting) after that it increases so he starts exercising at B
Q37 ans = D since when a limiting factor is introduced the population is either increasing or decreasing so B and C are wrong because they show a change and A is just wrong u cant have a constant environment

for Q.18 shudnt it take some time because he starts to breathe rapidly? u cant start directly i think
for Q.37 it says there is no limiting factors...

 

[Abu mota]

and for Q.18 how did u know that the oxygen isnt allowed to enter?

 

[Dsilentkila]

Assalam-o-alaikum wr wb...
this is bcoz the reaction is taking place...it is a slow reaction and therefore it will take time for the mass to decrease...it won't decrease DIRECTLY, like C!
hope that helps

$@l@m$!
The reaction rate decrease with time (as particles get used up [ concentration of reactants decrease]), thats why the gradient at the beginning is the greatest and it keeps on decreasing, i guess u can never have a constant gradient(line) coz reaction rates is not constant.

 

[Besterlinks]

IGCSE Biology > 2010 > Summer > qp12 > question 16...
Please explain.

 

[JOEJOE]

@Abumot 1)look theres an airlock.. this allows CO2 to leave but doesnt allow O2 to enter
2)Also they say that the guy who exercises takes a rest then works out
3)Look when u add a limiting factor the graph should go up or go down.. when theres no limiting fac the graph has its 4 stages lag, log, stationery and death phases.... as shown in D

Besterlinks because.. Ethanol or Lactic Acid are produced which contain high energy and energy produced relative to Aerobic respiration is low and during anaerobic respiration of yeast with sugar sometimes CO2 is produced or when making bread Co2 rises so yeah... Answer is B

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Can someone please explain this answer.. why can't it be C??

$@l@m$!
The reaction rate decrease with time (as particles get used up [ concentration of reactants decrease]), thats why the gradient at the beginning is the greatest and it keeps on decreasing, i guess u can never have a constant gradient(line) coz reaction rates is not constant.

Walaikumassalam wr wb..

yeahp...

 

[Alool]

can someone answer this question please.

i think it is C bcuz the side that is shady the auxin will be accumulated and hence that side would grow faster and the other side would bend..

 

[GorgeousEyes]

In jun00 qno 8..U knw that water is neutral so the ph in the end must be either A or B. Dilute sulphuric acid cannot be changed to a ph of 7 or more thatn 7 unless you use a strong base like NAOH so the answer is B.
In JUN00 qno 33 it is a rule that when u add an ammonium salt to a base ammonia is given out and ammonia turns litmus paper blue so the answer is A.
I dnt have Nov01 :/.
In Jun08 no 19, the best way to explain it is to look at the name before and after the reaction..the name still says
chromate(
VI) indicating that the chromate ions charge remains the same so the ans is either C or D. Then at the beginning of the question it says that excess NAOH was added and NAOH is a strong alkali(i.e soluble in water) so it will increase the pH of the mixture.
In jun09 qno 17..As u can c the forward reaction is breaking down a compund(liquid) by heating and so reversing it would be by adding water(cooling) and so the answer is B..and btw this is a test for water.
In jun2010 question no 26..for a reaction to occur in this question a reactive halogen should displace a less reactive halid from its compund. In group 7 the reactivity increases upwards and so the only choice where a reaction would occur is D becoz chlorine can displace iodide ions from their compunds being more reactive than them.

Thank youuu alooot really , I appreciate your help

 

[GorgeousEyes]

Assalam-o-alikum wr wb..
View attachment 12502View attachment 12503View attachment 12504View attachment 12505View attachment 12506View attachment 12507View attachment 12508
any doubt?

Masha'allah , Thaaanks alooot , I am grateful for your help

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Masha'allah , Thaaanks alooot , I am grateful for your help

Jazakallah Khair

 

[Besterlinks]

IGCSE Biology June 1994 Questions 4 and 23. Need help
.

 

[Ahmad Salah]

Can anyone post the link directly to the PDF file of the answers for chemistry paper 1 1994-2000...the website does not work for me except in this way

 

[Rania MD]

Any help with this question?

I answered A yet the correct answer is C.

The paper is November 2000

 

[Dsilentkila]

$alam$
i guess ive forgotten my basics ..
HeLp

 

[Maz]

$alam$
i guess ive forgotten my basics ..
HeLp

14) B- Since it's the main area for photosynthesis.
15) C - xylem

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Any help with this question?

I answered A yet the correct answer is C.

The paper is November 2000

Assalam-o-aalikum wr wb..
in my opinion it should be A...cuz there is no light...so auxins will accumulate on both the sides equally (they accumulate on the dark side) and therefore it should grow straight..

donno though! may be someone else can help you

 

[Rahma Abdelrahman]

Assalam-o-aalikum wr wb..
in my opinion it should be A...cuz there is no light...so auxins will accumulate on both the sides equally (they accumulate on the dark side) and therefore it should grow straight..

donno though! may be someone else can help you

I agree too, but I have a doubt here - Shouldn't the plumule show negative geo tropism as well? I don't know, I am confused here !