Syllogism — Premises: (a) All frogs are tortoises. (b) No tortoise is a crocodile. Conclusions: I) No crocodile is a frog. II) No frog is a crocodile.

Introduction / Context:
We combine a universal inclusion with a universal exclusion and test equivalent ways to state the same separation.

Given Data / Assumptions:

• Frogs ⊆ Tortoises.
• Tortoises ∩ Crocodiles = ∅.

Concept / Approach:
If all frogs are tortoises and no tortoise is a crocodile, then frogs share the same exclusion from crocodiles. Statements I and II are equivalent rephrasings of that separation.

Step-by-Step Solution:

Verification / Alternative check:
Venn diagram: Frogs inside Tortoises; Tortoises disjoint from Crocodiles; hence Frogs disjoint from Crocodiles.

Why Other Options Are Wrong:
Any option denying either I or II conflicts with the chain of inclusion and exclusion.

Common Pitfalls:
Missing that I and II are logically equivalent statements of disjointness.

Final Answer:
Both I and II follow.