### Instruction:

Extract the cause and effect entities from the following sentence:
For IST, prior knowledge of the surface type is required in order to allow selection of the most suitable retrieval algorithm

### Assistant:

KEYWORD: in order
VARIABLE: selection of the most suitable retrieval algorithm
CONDITION: to allow
CAUSE_1: IST
CAUSE_2: prior knowledge of the surface type is required
EFFECT_1: to allow selection of the most suitable retrieval algorithm

