Ποτε πρεπει να γραψω τη γενικη ελληνικη με και ποτε χωρις αρθρο; Που ειναι η διαφορα αναμεσα απο
The load of clothes is in the box. - Το φοριο των ρουχων ειναι στο κουτι.
There was a lack of food in Europe. - Υπηρξε μια ελλειψη τροφης στην Ευρωπη.
In the first example, it is implied that everyone knows which clothes we're talking about: the clothes from that load (=φορτίο). If you said "Το φορτίο ρούχων είναι στο κουτί." it would mean that the load of clothes rather than the load of oranges for example is in the box. Or even, that some books are in the box. So the meaning changes significantly as the emphasis is put on different words: load of clothes vs load of oranges vs something else completely which might not even be a load.
(By the way "φορτίο (των) ρούχων" sounds very unnatural, and is never used to describe a load of washing. It would only make sense as a large shipment of clothes.)
In the second example, it is stated that there is lack of food in general, not a specific amount/type of food. If you said "Υπηρξε μια ελλειψη της τροφης στην Ευρωπη" someone would ask: "Ποιας τροφής;" unless that was specified in a previous sentence.
But if this is the case, why do they say, my translation is incorrect? Or asked differently, shall I refer this as further right answers?
Regarding the last paragraph: this makes sense to me, as της is an article, so you're saying "There was a lack of the food in Europe," whence the question "Which food?" becomes perfectly natural. Is this a reasonable interpretation?