Q&A - PSLE Science

[atutor2001]

b) Each flower has both male and female parts. This is a structural adaptation that allows it to self-pollinate.


c) One advantage of self-pollination method is that the quality of the fruit will be maintained / will be the same. Through self-pollination, the new plant will be exactly identical as the parent plant and will produce fruits of the same quality as the parent plant.

[andante]

Hi all,

I would like to find out whether the following is structural or behavioural adaptation.
- an earthworm releases mucus to help it slide through the soil quickly when it is threatened.

My DD thought that it is structural adaptation. Pls advise.

[Pita]

vidhyalog:

Nebbermind:

I thought the bigger vol of air in X will push the ink to Y? Isn't it (1)? :?

Hi Nebbermind

That's what he answered first and I thought too. But then why is there the word \"immediately\". Because 2 things happen - at first - flask expands - and as air occupies space - the air in the flask will occupy the expanded space there causing the ink to momentary move towards X - before the air in X expands and therefore pushes it to the right.

This reasoning was given by my son when he noticed the answer he wrote was wrong. He then guessed it is because of the word immediately.

I find it quite sad that some questions may trip up children who can understand concepts - but are not so careful. But that is life I guess - you should know the concepts and be super-careful in reading the question.

Hi vidhyalog,

Here's what my son said after he read your post.

\"I feel that it is not necessarily true that the air in the flask will occupy the expanded space, because air does not have a definite volume, e.g. pumping 300 cubic centimetres of air into a 500 cubic centimetres container, the air spreads out to take up the entire space, retaining its volume. Therefore, air outside the flask in the plastic tube does not have to enter the flask to fill up the space. Thus, equal forces from both flasks in this case are pushing the water droplet, so it should not move at all :? That's what i think. Although my initial answer was (1), I am seriously beginning to have doubts.\"

Can someone please help to explain to my son?

:imcool: :?: :scratchhead: :idea:

Thank You!!!!

[ngbrdad]

Vanilla Cake:

Hi All,


MGS 2011 P6 Prelim Science paper is http://mwtuition.com.sg/free-resources but no answers are given. :please: help to check my younger sister's answers for the 30 MCQs of this paper. TIA.

Q1. Option 2
Q2. Option 3
Q3. Option 2
Q4. Option 4
Q5. Option 3
Q6. Option 4
Q7. Option 3
Q8. Option 1
Q9. Option 3
Q10. Option 3
Q11. Option 4
Q12. Option 2
Q13. Option 2
Q14. Option 1
Q15. Option 3
Q16. Option 4
Q17. Option 4
Q18. Option 4
Q19. Option 3
Q20. Option 4
Q21. Option 1
Q22. Option 3
Q23. Option 1
Q24. Option 4
Q25. Option 2
Q26. Option 3
Q27. Option 1
Q28. Option 2
Q29. Option 3
Q30. Option 4

If you disagree with any of the above suggested answers, pls advise the correct answers. OK and cheers. :snuggles:

Question 15 should be 4 instead of 3. From the graph the rate of photosynthesis does not increase after intensity 5. And the max rate of photosynthesis is at intensity 5 which is at depth 2m.

Question 22 should be 1. It is not known whether P3 and P5 are electrical conductor or not so can't really tell that the light bulb will light up.

[Vanilla Cake]

Vanilla Cake:

MGS 2011 P6 Prelim Science paper

Q15. Option 3
Q22. Option 3

ngbrdad:

Question 15 should be 4 instead of 3. From the graph the rate of photosynthesis does not increase after intensity 5. And the max rate of photosynthesis is at intensity 5 which is at depth 2m.

Question 22 should be 1. It is not known whether P3 and P5 are electrical conductor or not so can't really tell that the light bulb will light up.

Hi ngbrdad,
Thks for your helpful feedback.

Question 15 - I agree that the correct answer should be 4.

Question 22 - Pls revisit this question again. The materials are labelled as \"P1\", \"P2\" and \"P3\" and there is no \"P5\". As B1 and B5 light up when both S1 and S2 are opened, we can infer that P1 and P3 are conductors of electricity while P2 is an insulator of electricity.Thus when S2 is closed, B1, B3 and B5 will light up.

Pls advise your thoughts and thks again.

[ngbrdad]

Vanilla Cake:

Vanilla Cake:

MGS 2011 P6 Prelim Science paper

Q15. Option 3
Q22. Option 3

ngbrdad:

Question 15 should be 4 instead of 3. From the graph the rate of photosynthesis does not increase after intensity 5. And the max rate of photosynthesis is at intensity 5 which is at depth 2m.

Question 22 should be 1. It is not known whether P3 and P5 are electrical conductor or not so can't really tell that the light bulb will light up.

Hi ngbrdad,
Thks for your helpful feedback.

Question 15 - I agree that the correct answer should be 4.

Question 22 - Pls revisit this question again. The materials are labelled as \"P1\", \"P2\" and \"P3\" and there is no \"P5\". As B1 and B5 light up when both S1 and S2 are opened, we can infer that P1 and P3 are conductors of electricity while P2 is an insulator of electricity.Thus when S2 is closed, B1, B3 and B5 will light up.

Pls advise your thoughts and thks again.

Yup you are correct.
I read it wrongly and thought there were P1 to P5, not realising that P2 and P3 were repeated.

[Muku]

Hi, I need to check the answer to this question from 2010 SA1 CHS Paper Q25:


Four objects W, X, Y,Z are hung on a pole above ground, using strings of different lengths. The table shows the mass of each object and its distance from the ground.
[Object] [Mass/kg] [Distance from ground/cm]
[W] [3] [75]
[X] [10] [118]
[Y] [7] [19]
[Z] [3] [45]

Which of the following is true?
(1) Object X possesses the least potential energy.
(2) Object Y possesses the most potential energy.
(3) Object W has more potential energy than Object Z.
(4) Object Y possess more potential energy than Object W.

I thought the ans should be (3) but ans sheet says (4). The paper also had highlighting over the phrase \"using strings of different lengths\" in the question...so what is the correct answer and concept? Thanks in adv.

[P5G]

Please help.



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TIA.

[P5G]

Please help.


http://i56.tinypic.com/29nbdsp.gif\">

TIA.

[P5G]

Please help.


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TIA.