# Perfect question for answer below

The human eye has an aperture diameter of 24.2 mm .

Let's say that this sentence answer of a question . Which quesiton below would be the best one or are all question correct and do all questions mean the same ?

1) What diameter is the human eye ?

2) How many diameter of eye does a human have ?

3)How many diameter does the human eye have ?

4) What is the diameter of the human eye ?

• What are you basing these examples on? Some are close but others are very wide of the mark. Please explain which you think is correct & why the others can't be, otherwise we just have a proof-reading question, which is off-topic. Commented Jan 14, 2020 at 11:28
• This smells like homework. Commented Jan 14, 2020 at 17:46
• I am not a student . Commented Jan 14, 2020 at 20:11

Of the four answers offered, the best one is:

"1) What diameter Is the human eye ?"

I would suggest a couple of change to that though, to replace the upper-case 'I', and to remove the space prior to the question mark. That would make it:

"1) What diameter is the human eye?"

I would also note that, the question and answer may not match, in that human eyes (presumably) do not have a single diameter. However, if the question was on an exam paper (for example), and referred to a diagram, then perhaps it would make sense to have a single definitive answer such as 24.2 mm.

Hope that helps,

Alan.

• What about the other questions?Are all grammatically correct ? Commented Jan 14, 2020 at 11:22
• Hi - None of the others are grammatically correct. Of those three, only (4) is close, and it would have to have 'the' added to it to make it grammatical: "4) What is the diameter of the human eye?". Alan.
– Alan
Commented Jan 14, 2020 at 11:36

Both 1 & 4 are grammatically correct. However, they are not specific to the aperture, so the answer you're likely to get to those questions is the overall diameter of the human eye. To ask those questions clearly you would need to add to them.

``````1) What diameter is the the aperture of the human eye?

4) What is the diameter of the aperture of the human eye?
``````

2 & 3 have a number of problems which I'm not expert enough to explain in detail, but among them are that diameter is treated as a plural when it is a single measurement and the use of 'have' is not the correct possessive for this situation.

For me, option 4 is fine, though I'd probably be more specific, in alignment with the answer:

What is the aperture diameter of the human eye?

• What I want to ask is that The human eye has diameter of 24.2 mm . While I was asking question I couldn't understand why I can't say '' What diameter does the eye have ? Why we can’t use the verb”have” ? Commented Jan 14, 2020 at 17:00