唔該!!關於科學

1.when we observe onion cells under a microscope,why is iodine solution added?
Ans: It is because the nucleus will be dyed to a deeper colour and let us look at the cells more easily under the microscope.

b. which of the above cells is a cell taken from a plant?give two reasons to support answer.
我唔知above cells係邊D, 答唔到你.
不過give two reasons 可以幫到你(俾你3個ans, 睇下你邊個正確啦):
- Firstly, there is a cell wall that protects, supports and gives shape to the plant cell. Only plant cells have cell wall.
- Secondly, there are chloroplasts that contain chlorophyll to carry out photosynthesis to make food. Only plant cells have chloroplasts.
- Thirdly, there is a big vacuole. Only plant cells have big vacuoles.
- Lastly, the cell has a regular shape. Only plant cells have regular shapes but animal cells have irregular shapes.

c.what is the function of component(I)
Sorry, I don't know the ans.

d..where can you find genetic materials in cell b
我唔知個cell b係點樣喎, 好難答你...cell b 是不是human sperm or human egg?? If yes,
the Ans : nucleus

2006-12-30 00:20:11 補充：
Sorry, 呢句應該係 俾你4個ans, 唔係俾你3個ans, sorry.