In the following questions below are given four statements followed by three conclusions numbered I, II & III. You have to take the given statements to be true even if they seem to be at variance from commonly known facts. Read all the conclusions and then decide which of the given conclusions logically follows from the given statements disregarding commonly known facts.

Statements: 

Some fish are crocodiles.

Some crocodiles are snakes.

No snake is tortoise.

All tortoises are frogs.

Conclusions: 

I. No snake is frog.

II. Some snakes are fish.

III. Some fish ate frogs.