Q&A - PSLE Science

[pertunia]

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[Little Einstein]

pertunia:

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Its so easy, because there is no chloroplast

[G Tan]

Little Einstein:

pertunia:

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Its so easy, because there is no chloroplast

yup, because onion do not need to make food, so no chloroplast

[pertunia]

I thought only leaves have chloroplast since only leaves have chlorophyll and make food? Balsam stem cell also have chloroplast? Please enlighten me. Thanks a lot.

[Jennifer]

No shortcut:


- must understand what the question is
- able to apply the right concept/reasoning
- elimination method w/o knowing the above 2 points is not very helpful

JMHO

[cimman]

pertunia:

I thought only leaves have chloroplast since only leaves have chlorophyll and make food? Balsam stem cell also have chloroplast? Please enlighten me. Thanks a lot.

some stems do have chloroplasts and produces food.
check out this link and scroll to Page 165, bottom section: Photosynthetic Stems: http://www.edupub.gov.lk/Scieence%208%28E%29/Chapter%206.pdf
also check out this pic of a balsam plant and it does have green stem: http://home-and-garden.webshots.com/photo/1181052099042988353KaBRFn

the key question though is why do some plants have photosynthetic stems ? Cactus have it because their leaves are a spindle and does not have the surface area to produce food. But the balsam plant have good broad green leaves which produces food, so why the photosynthetic stem ?

I found an article on this, it's very dry though and unfortunately, you have to pay for the entire article:
http://www.jstor.org/discover/10.2307/2389755?uid=3738992&uid=2129&uid=2&uid=70&uid=4&sid=56245820003

[pertunia]

Hi Cimman,


Thanks for the information. Really appreciate it a lot.

[Champion]

First step --1st - the child needs to be careful in reading the questions. Highlight the keyword in the question, then analyse the given choice. I share here one question that was in my P4 DD1 SA1 MCQ.


Which of the following is definitely true about plants?
A) ALL plants start their life cycles from seeds.
B) Plants reproduce to ensure the survival of their kinds.
C) Seeds need oxygen, water and sunlight to germinate.

(1) A only
(2) B only
(3) A and B only
(4) A, B and C

DD1 highlighted the keywords (as I done above) and then proceed to eliminate her answers by striking off (1) & (4). So left (2) & (3) then \"unconsciously\" she forgotten to strike off (3) and \"conveniently\" puts her answer as (3) when the correct answer is (2)! :frustrated: :stompfeet: :slapshead: :mad:

The Science T has let the class tried similar questions a few times, but this question is a little rephrase and concept changed and so my dear DD1 careless mistakes that cost her to lose this precious 2 marks :sad:

[Chan09]

Need help on this as answer key is 1.


My understanding is lead is a conductor of electricity and D is a closed circuit.



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[isetan]

Chan09:

Need help on this as answer key is 1.


My understanding is lead is a conductor of electricity and D is a closed circuit.



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Hi chan09,

My ans is (3). Option B has no batteries, option D has a parallel loop, and I also agree lead is a conductor of electricity.