Challenge 1: Fruit Color Facts and a Query — Possible Solution
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SWI-Prolog session:

    ?- assertz(color(banana, yellow)).
    true.

    ?- assertz(color(apple, red)).
    true.

    ?- assertz(color(grape, purple)).
    true.

    ?- color(banana, X).
    X = yellow.

(Alternatively, these three facts could be written directly into a
.pl file and loaded with consult/1, rather than asserted interactively
-- both approaches add the same facts to the database.)

Explanation:
Each color(Fruit, Color) fact states a genuinely true relationship
between a specific fruit and its color, added to Prolog's own
database. Querying color(banana, X) asks "for what X is
color(banana, X) true?" -- Prolog searches the database, finds the
one matching fact, and binds X to yellow, exactly the query behavior
the chapter introduces.

WHY THIS WORKS AS AN ANSWER
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This adds three genuine facts matching the chapter's own parent/2
example shape, then queries one of them for a single unknown value,
directly demonstrating the fact-then-query workflow.