Q&A - PSLE Science

[stary]

Part 1

Hi all,
Need explanation for some questions.

F1RST Question:
(MGS/CA1/Primary 5/2009)
Question 14:

Lionel planted some seeds in a pot. He watered them every day. After a few weeks, plants grew in the pot. Later, the plants died. Which of the following is/are correct conclusion(s) of this experiment?

A: Plants can grow over time.
B: Plants come from seeds.
Plants will die.
Plants need water.

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

My answer: 3
Answer sheet: 2
Whose is correct (and why?)

[stary]

Tang:

elkniwt:

Hi,


Need help on this qn :

Should the ans be (2) or (3)? Pls advise. Thanks.
http://i56.tinypic.com/oshfki.jpg\">

From the foodweb, A is the food producer. B is a herbivore while C is a omnivore.
C (a predator) preys on B (a prey).
Eating plants cannot be considered as a predator. So B is not a predator.
So answer is (2) - C only.

Hi Tang,

It is not necessary that 'A' must be a food producer. It can be a prey too.

Best Regards.

[stary]

Part 2

Hi all,
Need explanation for some questions.

2ECOND Question:
(Ai Tong/SA1/Primary 5/2009)
Question 14:

Which statement(s) about germination of a seed is/are correct?

A: During germination, the seed needs air, sunlight, water, food and warmth.
B: A seed does not need to make food.
Water is needed for germination to occur.
Fertiliser must be added to the seed for germination to take place.

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

My answer: 3
Answer sheet: 1
Whose is correct? (And why?)

[stary]

My explanation for the above:


I chose B as the seedling did not have first leaves to make its own food so it depends on the seed leaves for food.

[stary]

Part 3

Hi all,
Need explanation for some questions.

Question THR33:
(Rosyth/CA1/P6/2010)
Question 9:

http://www.flickr.com/photos/64113082@N03/6111701035/in/photostream

If sexual reproduction takes place between the two trees, which are the characteristics the young of the tree can inherit?

A: Types of leaves
B: Height of the tree
Colour of the flower
Thickness of the trunk

1) D only
2) A and C
3) A, B and C
4) All of the above

My answer : 4
Answer key: 2
Fact: I thought the height and thickness of the tree can be inherited?
(It's just like the height and size of us [humans]!)

[stary]

Many thanks (if you've helped me)!!!

[atutor2001]

Hi Stary


1. In the food web, "A" must be the food producer. If "A" is not the food producer, then it cannot be called a "food web" because all food webs must have food producer/s.

2. The question is regarding "germination of a seed". With very strict interpretation, the question is limited to "conditions needed for germination." Therefore, the information that "A seed does not need to make food" is not related to condition for germination of a seed. I share your disagreement and imo, it is another "siao" question.

3. I agree with your interpretation that height and trunk thickness of trees can also be genetic traits for some types of trees. However, generally speaking, most trees have about the same kind of height and trunk thickness and are affected by the condition of the soil, etc. So at Pr level, these 2 points should be treated like the length of hair or nail and are NOT passed down genetically.

[stary]

Thanks atutor2001 for your prompt explanation.

[chrisu]

Question on population from Longman My Weekly Companion Science Book B;

http://img.photobucket.com/albums/v160/guppiesonli/Misc/QPopulation.jpg\">

I've problem explaining to my daughter on population in the sense as how to differentiate them. Anyone can explain in detail on how to derive the answer? Thank you.

[Tang]

chrisu:

Question on population from Longman My Weekly Companion Science Book B;

http://img.photobucket.com/albums/v160/guppiesonli/Misc/QPopulation.jpg\">

I've problem explaining to my daughter on population in the sense as how to differentiate them. Anyone can explain in detail on how to derive the answer? Thank you.

Hi,

My answer is (1) - 5.

Label the animals given as follows from left to right and top to bottom.
A B C D
E F G H

A and G - same population, damselfly.
B and D - same population, mosquito.
C and E - same population, frog.