Translation:The Israeli tourist is resting underneath the tree.
Beneath and under have the same meaning. Restricting the correct answer to only one word out of several with the same meaning is too rigid. Using a larger vocabulary is beneficial in a language instruction program.
Yes, of course. I think this is a combination of spending less time on each individual sentence in order to get the course into beta (and available to the general public) more quickly, and not being able to think of all possible synonyms while you are typing up the acceptable translations for each individual sentence.
So you can expect to find many correct sentences incorrectly rejected; part of the beta period is that we help the course maintainers by reporting such missing translations, so that they can add them more easily.
So please report any missing translations that you come across, when you are fairly sure your translation is correct -- not here in the sentence discussions but through the "Report a problem / my translation should be accepted" button or the flag icon that is shown when a sentence is rejected during an exercise.