Q&A - PSLE Science

[starlight1968sg]

tianzhu:

How does one phrase and write answers expected by examiners?


For the benefits of PSLE 2010 students,it would be useful for members to share some of their thoughts.

Best wishes

Beats me!
Armed with facts and knowledge gets a barely pass for Sc Sect b only.

[tianzhu]

Hi


The search for the well worded PSLE Science answers goes on.

When this PSLE Science thread was first started, its pages were blank. Slowly,members put words into them.

Judging by the number of hits in the threads on DSA and Gifted Education, there are many well informed parents and smart kids in KSP.Besides this, there are also many teachers and learning centres in this forum. If this group of members were to put in one line each, this thread would be flooded with valuable tips.

Hope ends when you stop believing in it. Hope is one of the most exciting things in life. If you believe in it, it will come. Even if it doesn’t come immediately, there is always a chance that it’ll come later.

Best wishes

[baibai06]

Hi........

i am about to take PSLE this year

i came across a question showing a fish tank with a fish and hydrilla and the fish tank is placed
in sunlight, but yet the fish died after 12hours or so during the night that day....
the fish were given no food.....
so can we say that the fish ate the plants, and therefore there were no more plants that photosynthesised and produced oxygen, there the fish died due to a
lack of oxygen?

i heard that it was not reconmmended to say that fish ate the plants.....
can anyone clarify about that?
thanks :?

[Muffins]

baibai06:

Hi........

i am about to take PSLE this year

i came across a question showing a fish tank with a fish and hydrilla and the fish tank is placed
in sunlight, but yet the fish died after 12hours or so during the night that day....
the fish were given no food.....
so can we say that the fish ate the plants, and therefore there were no more plants that photosynthesised and produced oxygen, there the fish died due to a
lack of oxygen?

i heard that it was not reconmmended to say that fish ate the plants.....
can anyone clarify about that?
thanks :?

Ah... Here is the clue. It died during the night. In the night the plant would only respire, thus taking in too much oxygen, so the fish and the plant would have to compete for air. In the end, the fish died due to too little air being taken in by it....

[kitty2]

What’re the similarities between the lung and fish gills?Anyone can help?


Thanks

[P5G]

kitty2:

What're the similarities between the lung and fish gills?Anyone can help?


Thanks

Here are my answers.

Both organs have many blood vessels.

Both organs have large surface areas to absorb oxygen.

Both organs are for exchange of gases.

[P5G]

Please help.


Q23. The diagram below shows Kenny's family tree of 4 generations that carry the genetic trait of a disease, D. Study the family tree carefully and answer the following question.


Please refer attachment for the family tree
http://www.orlesson.org/orp/09Sc/2009-Sc-SA2-CHS.pdf


Which of the following statements are conclusions you can draw about the above famly tree?

A. Disease D is passed on to only the male members of the family.
B. There is a chance that Kenny's sister may bear a son with the disease.
C. The daughter of a male patient with Disease D will be a carrier of the Disease.
D. Kenny's mother inherited the genes of Disease D from her maternal grandmother.

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


My answer is (1) while the answer in the worksheet is (3). Which is correct?


TIA.

[atutor2001]

P5G:

Please help.


Q23. The diagram below shows Kenny's family tree of 4 generations that carry the genetic trait of a disease, D. Study the family tree carefully and answer the following question.


Please refer attachment for the family tree
http://www.orlesson.org/orp/09Sc/2009-Sc-SA2-CHS.pdf


Which of the following statements are conclusions you can draw about the above famly tree?

A. Disease D is passed on to only the male members of the family.
B. There is a chance that Kenny's sister may bear a son with the disease.
C. The daughter of a male patient with Disease D will be a carrier of the Disease.
D. Kenny's mother inherited the genes of Disease D from her maternal grandmother.

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


My answer is (1) while the answer in the worksheet is (3). Which is correct?


TIA.

(3) is correct.

[Tang]

atutor2001:

P5G:

Please help.


Q23. The diagram below shows Kenny's family tree of 4 generations that carry the genetic trait of a disease, D. Study the family tree carefully and answer the following question.


Please refer attachment for the family tree
http://www.orlesson.org/orp/09Sc/2009-Sc-SA2-CHS.pdf


Which of the following statements are conclusions you can draw about the above famly tree?

A. Disease D is passed on to only the male members of the family.
B. There is a chance that Kenny's sister may bear a son with the disease.
C. The daughter of a male patient with Disease D will be a carrier of the Disease.
D. Kenny's mother inherited the genes of Disease D from her maternal grandmother.

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


My answer is (1) while the answer in the worksheet is (3). Which is correct?


TIA.

(3) is correct.

Hi,

Yes, B is correct if she marries someone who suffers from disease D.

[kitty2]

P5G:

kitty2:

What're the similarities between the lung and fish gills?Anyone can help?


Thanks

Here are my answers.

Both organs have many blood vessels.

Both organs have large surface areas to absorb oxygen.

Both organs are for exchange of gases.

Thank you