Question

Choose the correct option for the following syllogism.
All animals are birds.
Some pigeons are animals.
All ostriches are pigeons.

Conclusion:
I. All ostriches are birds.
II. Some ostriches are birds.
III. Some birds are pigeons.
IV. All pigeons are birds.

Only I follows
Only II follows
Only I and III follow
Only III follows​

Answer 1

Answer:

4 one

Explanation:

all pigeons are birds

Answer 2

CONCLUSION: Some birds are pigeons i.e only III follows. (option 4)

• All animals are birds ⇒ This statement is universal affirmative.
• Some pigeons are animals ⇒ This statement is a particular affirmative.
• All ostriches are pigeons ⇒ This statement is a particular affirmative.

Understand, the statements together:

"All animals are birds" + "Some pigeons are animals" suggest that  

"Some pigeons are birds".

1. Some pigeon ⇔ animals
2. All animals ⇔ birds  (remember, all birds are not animals)

∴  Some pigeons ⇔ birds

• The last statement states that all ostriches are pigeons.

    3. All ostriches ⇔ pigeons (remember, all pigeons are not ostriches)

• All ostriches are pigeons but not all pigeons are ostriches, thus we cannot determine whether any amount of ostriches are birds/animals.

• No further conclusions can be made.

The conclusion we have is "Some pigeons are birds".

"Some pigeons are birds" ⇔ "Some birds are pigeons"

Conclusion: Some birds are pigeons (only III follows)