Q&A - PSLE Science

[Sun_2010]

P5G:

Please help.


16. The table below shows the number oif organisms in a habitat.

Organism | Number of organisms
--------------------------------------
Ixora |2
Mynahs | 3
Slugs | 7
Butterflies | 11
Snails | 9
Caterpillars | 7

How many populations of animals are there altogether?

(1) 39
(2) 37
(3) 5
(4) 4

Given answer: (4)

Should the correct answer be (3)?

TIA.

Given answer is correct

Ixora - flower not animal
1. Mynahs
2. Slugs
3. Butterflies and Caterpillars - they are the same population
4. Snails

[benleetube]

Hi everyone. I need help for a question:


Why do fish stalls use small pieces of ice to store/display the fish instead of using big pieces of ice?

Thanks in advance.

[P5G]

13. A ball is bounced on the ground as shown below.


See picture
http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA1-NanHua.pdf

Which of the following statements about the ball above are true?

A: The kinetic energy is zero at Point X.
B: The kinetic energy is the highest at Point Z.
The potential energy is the highest at Point X.
The ball has both potential and kinetic energy at Poiint Y.

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

Given answer (4).

Should the correct answer be (1).

TIA.

[Nebbermind]

starlight1968sg:

What? add bleach and duckweed will grow better ??? :yikes:

out of curiosity I search and found that there r experiment on how 'sterilized' duckweed will affect its growth/production. but is this topic covered in pr sch syllabus?

[mother777]

benleetube:

Hi everyone. I need help for a question:


Why do fish stalls use small pieces of ice to store/display the fish instead of using big pieces of ice?

Thanks in advance.

Hi,

I think the reason for using small pieces of ice to store/display fish instead of using big pieces of ice is mainly to increase the surface area of contact.

Many small pieces of ice will have a larger surface area of contact with the fish compared to 1 big piece of ice. Larger the surface area, the better chilling affect on the fish making the fish stay fresh for a longer period of time.

Hope this is correct :scratchhead:

[Nebbermind]

P5G:

13. A ball is bounced on the ground as shown below.


See picture
http://www.orlesson.org/orp/10Sc/2010-P6-Sc-SA1-NanHua.pdf

Which of the following statements about the ball above are true?

A: The kinetic energy is zero at Point X.
B: The kinetic energy is the highest at Point Z.
The potential energy is the highest at Point X.
The ball has both potential and kinetic energy at Poiint Y.

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

Given answer (4).

Should the correct answer be (1).

TIA.

I think the only doubt is (B) but if only comparing the 3 positions, then (B) is true.

[mother777]

Nebbermind:

starlight1968sg:

What? add bleach and duckweed will grow better ??? :yikes:

out of curiosity I search and found that there r experiment on how 'sterilized' duckweed will affect its growth/production. but is this topic covered in pr sch syllabus?

Hi Nebbermind,

I agree, was baffled when read this question. When i googled, got sites telling how to grow duckweed and affect of bleach on it.

Bleach in minute amount (small amounts) is used to kill the bacteria and organisms affecting duckweek growth. The duckweek is supposed to be rinsed in bleach for 10~30 seconds to kill the micro-organisms. This will allow unhindered growth of the duckweed.
But if you rinse it for long time, the duckweed itself will be bleached and die.

So I am confused here too...

[mother777]

Nebbermind:

starlight1968sg:

What? add bleach and duckweed will grow better ??? :yikes:

out of curiosity I search and found that there r experiment on how 'sterilized' duckweed will affect its growth/production. but is this topic covered in pr sch syllabus?

Hi Nebbermind,

I agree, was baffled when read this question. When i googled, got sites telling how to grow duckweed and affect of bleach on it.

Bleach in minute amount (small amounts) is used to kill the bacteria and organisms affecting duckweek growth. The duckweek is supposed to be rinsed in bleach for 10~30 seconds to kill the micro-organisms. This will allow unhindered growth of the duckweed.
But if you rinse it for long time, the duckweed itself will be bleached and die.

So I am confused here too...

[hashroop]

hashroop:

Hi, pls help. For a developing human foetus, which system(in correct order) develops first.

Circulatory, muscular, skeletal,digestive, respiratory?

Thanks

resending...thx

[Nebbermind]

i think the circulatory gwah. That wld be the main mean to transfer nutrients from mom to foetus for it to build the rest.