Statements: All tigers are jungles. No jungle is bird. Some birds are rains. Conclusions: No rain is jungle. Some rains are jungles. No bird is tiger.

All tigers are jungles. No jungle is bird.

Since both the premises are universal and one premise is negative, the conclusion must be universal negative (E-type) and should not contain the middle term.

So, it follows that 'No tiger is bird'. III is the converse of this conclusion and so it holds.

No jungle is bird. Some birds are rains.

Since one premise is particular and the other negative, the conclusion must be particular negative (O-type) and should not contain the middle term. So, it follows that 'Some jungles are not rains'.

Since I and II also involve the same terms and form a complementary pair, so either I or II follows.