what's the meaning of fall back on in this context?

[bibos]

English Language Tests, Intermediate level

ESL/EFL Test #176 "Phrasal idioms with the verb 'fall'", question 6

A Brussels-based think tank reported that Europe is ......... Asia in terms of education and skills.

(a) falling behind
(b) falling behind in
(c) falling back on
(d) falling off

English Language Tests, Intermediate level

ESL/EFL Test #176 "Phrasal idioms with the verb 'fall'", answer 6

A Brussels-based think tank reported that Europe is falling behind Asia in terms of education and skills.

Correct answer: (a) falling behind
_________________________

what's the meaning of fall back on in this context?

bibos

[Mister Micawber]

It is a wrong answer in this context, but

fall back on / upon,
a. Also, fall back to. to retreat to: They fell back on their entrenchments. The troops fell back to their original position.
b. to have recourse to; rely on: They had no savings to fall back on.
_________________
Native English teacher at Mister Micawber's

[Saneta]

A Brussels-based think tank?

please explain
thanks

[Mister Micawber]

Which words do you not understand, Saneta? They are all readily available in the DICTIONARY.
_________________
Native English teacher at Mister Micawber's

[Beeesneees]

http://www.onelook.com/?w=think+tank&ls=a
_________________
Cheers m' dears!