Can I walk into a room with forks in my hand and ask this question?
Yes, you can.
in sound how do you tell the difference between fork and tea in this case?
They have different tones.
叉 - chā - fork
茶 - chá - tea
The tips for the first skill in the course explains the different tones.
Isn't it "wants" as opposed to needs
Wish, want, need, lack, miss -- are fuzzy points on a sliding scale of semantics
Yes, if you can use it freely, you know you've reached a milestone in Chinese.
Yes, the sentence lacks accuracy, which assumes definition-wise instead of meaning-wise.
Most of the time, 要 means to want.
Duo accepts both "needs" and "wants"
What is the difference between 叉 and 叉子 ?
叉子 only means fork, while 叉 can also mean "a cross" or "X" (as in "mark the wrong answers with a cross/ X) or the action of crossing / intersecting.
Why no 吗 or 要不要?
谁 marks the question.
Is this sentence as ambiguous in Chinese as it is in English? In English it can mean "which one(s) [of you] needs a fork?" but also "why would anyone need a fork?"
Yes, it depends on context
Here is it "needs", but last one is "wants" and "needs" is not acceptable in that one sentence
the a can be silent geez i cant move in this level because of that