Read the poem and answer the question. Grey geese glided, glad and grave, The marsh held secrets, dark and deep; The lake was a mirror of moving sky, And reeds stood watch while herons sleep. The frogs croaked like a rusty gate, The lilies leaned in silver rain; Soft ripples ran from root to root, And dawn was a lantern again. "And reeds stood watch while herons sleep" is personification because: