Q&A - PSLE Science

[portal]

I have this qustion to ask.Substance x has to pass through various parts of a plantcell before reaching the nucleus.Which list below shows the correct order in which substance x has to pass through.

1]cellmembrane-cytoplasm-cellwall
2]cellwall-cellmembrane-cytoplasm
3]cellmembrane-cellwall-cytoplasm
4]cytoplasm-cellmembrane-cellwall
What is the ans.

[G Tan]

portal:

I have this qustion to ask.Substance x has to pass through various parts of a plantcell before reaching the nucleus.Which list below shows the correct order in which substance x has to pass through.

1]cellmembrane-cytoplasm-cellwall
2]cellwall-cellmembrane-cytoplasm
3]cellmembrane-cellwall-cytoplasm
4]cytoplasm-cellmembrane-cellwall
What is the ans.

answr is 2

[portal]

Thanks for the help

[portal]

I have this question to ask.

Which of the following statements about human reproduction is true?

A-To produce an offspring, two differnt sex cells are needed.
B-Sperm cells are made in large numbers in a special organ called the ovary.
C-A healty female normally produces an egg cell once in every three months.
D-The sperm cell carries half of the information needed for reproduction and the egg cell carries the other half.

1)A and B
2)B and C
3)C and D
4)A and D

[tianzhu]

portal:

I have this question to ask.

Which of the following statements about human reproduction is true?

A-To produce an offspring, two differnt sex cells are needed.
B-Sperm cells are made in large numbers in a special organ called the ovary.
C-A healty female normally produces an egg cell once in every three months.
D-The sperm cell carries half of the information needed for reproduction and the egg cell carries the other half.

1)A and B
2)B and C
3)C and D
4)A and D

Hi

In males, the testes produce sperm.

In females, from puberty, an egg is usually released from one of the ovaries every month.

So, this eliminates (1), (2) and (3).

The male produces reproductive cells called sperms.The female produces reproductive cells called eggs. The sperm cell carries half of the information needed for reproduction and the egg cell carries the other half.

The answer is (4).

Best wishes

[fightingmom]

http://i39.tinypic.com/24fgy79.jpg\"> Hi all,


This is taken from Ai Tong 2011 CA1 Q24. The answer provided was (2) but I think it should be (3)...

Anyone can confirm / help ?

TIA !

[fightingmom]

http://i43.tinypic.com/2956b2p.jpg\"> Hi all,


Can also help with this question also from Ai Tong 2011 CA1 Q25? Answer provided was (1) but i think it is (4) ... :?

Please help

TIA !

[fightingmom]

Hi again,


Sorry , can anyone also help with the following question: http://i41.tinypic.com/kdsldl.jpg\">

The answer sheet is (4) but my answer is (3)... eh... possible for anyone to enlighten me why (4) ?

TIA !

[mathfreak]

fightingmom:

http://i43.tinypic.com/2956b2p.jpg\"> Hi all,


Can also help with this question also from Ai Tong 2011 CA1 Q25? Answer provided was (1) but i think it is (4) ... :?

Please help

TIA !

I think it's (4) too. Diagram C is almost certainly that of a wind-dispersed plant.

[mathfreak]

fightingmom:

Hi again,


Sorry , can anyone also help with the following question: http://i41.tinypic.com/kdsldl.jpg\">

The answer sheet is (4) but my answer is (3)... eh... possible for anyone to enlighten me why (4) ?

TIA !

Solution:
When the steel bar AB was magnetised, the North pole of the magnet was touching the steel bar. That means the end of the steel bar from which the magnet was removed would become a South pole, as, in simple terms, the magnetism \"things\" in the steel bar which have a South polarity would be attracted to the magnet and be \"dragged\" across to the end of the steel bar. This means the top of the first thumbtack is a North pole, its tip is a South pole, the top of the second thumbtack is a North pole, its tip is a South pole, the top of the third thumbtack is a North pole and finally its tip is a South pole. Since like poles repel, the thumbtack would move away from the magnet. Hence the answer is (4).