Can I write this down?

[NGKEVEN]

Can I write "Plant cells have cell walls."on the exam paper?My teacher's anwser is"Plant cells have a cell wall."A plant cell has a cell wall,so I think many cells have many cell walls.But why there is an 'a' in the answer?

[svartnik]

Can I write "Plant cells have cell walls."on the exam paper?My teacher's anwser is"Plant cells have a cell wall."A plant cell has a cell wall,so I think many cells have many cell walls.But why there is an 'a' in the answer?

I see your point. Both versions are accepted English.

[bhaisahab]

Plant cells (in general) have a cell wall (one cell wall).
Dogs (in general) have a tail, a head and 4 legs.

[svartnik]

Plant cells (in general) have a cell wall (one cell wall).
Dogs (in general) have a tail, a head and 4 legs.

(More than one) plant cells have (more than one) cell walls.

Logic aside, both are accepted.

'Plant cells have walls' means either one plant has several walls or one plant has one wall or several plants have one wall they 'use jointly'. It is in the shared knowledge of the speaker and the hearer what is meant by this sentence, so I think both the singular and plural work. As long as the plural/singular usage does not go to the detriment of coherence, use either of them.

[jctgf]

just a student.
I think that the cell wall is considered one structure only. its format is spherical, it has no sides and it doesn't have the format of a cube. it's a continuous structure, like he skin of an egg.
just a student.

[svartnik]

just a student.
I think that the cell wall is considered one structure only.

So does anybody else, myself included.
(anatomy) a layer (a lining or membrane) that encloses a structure
You are missing my point.

[bhaisahab]

So does anybody else, myself included.
(anatomy) a layer (a lining or membrane) that encloses a structure
You are missing my point.

No, I think that you are missing our point which is, when one speaks about 'cell walls' one is speaking about cells in general and cells in general have one cell wall.

[jctgf]

So does anybody else, myself included.
(anatomy) a layer (a lining or membrane) that encloses a structure
You are missing my point.

no need to be angry. I agree with you, as you seem to agree with Bhaisahab.
I took the opportunity to exercise my writing, even without adding anything new to the post.
regards!

[svartnik]

no need to be angry. I agree with you, as you seem to agree with Bhaisahab.
I took the opportunity to exercise my writing, even without adding anything new to the post.
regards!

Angry? I do not even know the meaning of the word.