Statements: All flowers are trees. No fruit is tree. Conclusions: No fruit is…

Concept: In a syllogism, combine the two premises through the term common to both (the 'middle term'). A conclusion follows only if it can be validly derived from that combination. In addition, a universal-affirmative premise of the form 'All A are B' also permits its converse-by-limitation, 'Some B are A', under the standard convention (used throughout these problems) that every class mentioned is non-empty.

1. Premise 1 gives: the flower class is entirely inside the tree class.

2. Premise 2 gives: the fruit class shares nothing with the tree class.

3. Since the flower class is entirely inside the tree class, and the fruit class shares nothing with the tree class, the fruit class can share nothing with the flower class either -- so 'No fruit is flower' necessarily holds. This validates conclusion I.

4. Premise 1, 'All flowers are trees', is a universal-affirmative statement. By conversion-by-limitation (assuming the flower class is non-empty), it also yields 'Some trees are flowers'. This validates conclusion II.

Cross-check: picture the tree circle fully containing the flower circle, with the fruit circle drawn completely outside the tree circle. The diagram shows the fruit circle and the flower circle never touch (confirming conclusion I), and it shows the flower circle is a genuine, non-empty portion of the tree circle (confirming conclusion II). Both conclusions hold at once and neither depends on the other.

Result: Both I and II follow.