alertness

The guard's alertness prevented a potential theft.

警備員の警戒心が潜在的な盗難を防いだ。

The driver's alertness prevented a collision.

運転手の警戒心が衝突を防いだ。

His alertness during the exam helped him answer all questions correctly.

試験中の彼の明晰さがすべての質問に正しく答えるのを助けた。