answers for week 4

Dear all,

Here are the answers.

English Synthesis and transformation:

Q1. Gary asked Peta why he had to play soccer the following/next day.

Q2. Teddy told Ben that that hotel had been demolished thousand of years ago.

Q3. Peter asked if /whether they were still going for that workshop then.

Q4. Mary asked if/whether she had to be a Singapore citizen in order to qualify for that scholarship award.

Q5. Mother asked if/whether I was certain I had remembered to take out the clothes from the laundry the previous night.

Science

Q1. What do you think caused cell X to burst?

Topic: Cells
Concept: Animal and Plant cells have different parts and functions. Cell wall and chloroplast are not present in animal cells.

Answer: 
The Cell X absorbed more water than its cell membrane could hold or The cell does not have a cell wall to contain the water.

Explanation: The cell wall is an important part of the plant cell to hold the cell in place and protect the cell from the outside. The cell membrane of both cells are semi-permeable (only allows some items to pass in and out through the cell) and without a cell wall to hold the cell in place, cell X will burst when too much water is absorbed. On the other hand, the cell wall for Y protects the cell.

Q2.

Answer:
The cell wall of Cell Y supported the cell structure and was strong enough to prevent it from bursting.

Topic: Magnets

Concept: Magnetic objects can be magnetized by the stroking method. Like poles attract, unlike poles repel. A magnet has a North pole and a South pole on each opposite end.

Answer:

Part (A) i and ii
C: South Pole
D: North Pole

Part (B)

Both of the poles of steel bar XY would be like poles (South and South). A magnet has two unlike poles in which both the unlike poles of the magnet has the ability to attract and repel other magnets. In this instance, both the ends are like poles and it does not fulfil the characteristic of a magnet.

Topic: Heat (Expansion and Contraction)
Concept: Heat expands items, Cool air contracts items.

Answer: The metal bridge will crack and might collapse. The gaps allow for the metal structure to expand during a very hot day due to the heat and contract during a cool day. If there is no gaps for the metal structure to expand, it will be compressed and the structure will push against each other, resulting in a crack and collapse of the bridge.

Explanation: There are two parts to the answer. The first part is an observation of what happens to the bridge when there are no gaps on a very hot day. The second part involves the use of concepts and key words to explain the answer.

The gaps allow for expansion and contraction (not just expansion only) during hot and cool days. This gives space for the processes to take place. Without the gaps, the structure will push against each other and will crack.