そばはそば粉から、うどんやきしめんは普通の小麦粉からできてるの。

、。

Soba is made from buckwheat flour; udon and kishimen are made from regular wheat flour.

Literal

Soba [topic-は] buckwheat-flour [from-から], udon [or-や] kishimen [topic-は] ordinary [gen-の] wheat-flour [from-から] are-made [explanation-の].

A factual food sentence demonstrating the ~からできる pattern 'made from X,' where から marks the material source. ~や is the non-exhaustive list particle 'A and B (among others).' きしめん is a flat, wide noodle from Nagoya; うどん is its familiar thick counterpart — both are wheat-based and distinct from the buckwheat-based そば. Final の is the feminine/casual explanatory.