What did mary cassatt express in her painting mother and daughter?

She documented and preserved her view of the world.

This painting doesn't represent a historical event, or a political statement, or a functional object. It represents a personal theme that Cassatt obsessed over, and that is the relationship between a mother and a child, within the framework of the women's inner lives and psychology. The painting depicts an intimate scene of motherly warmth and love. The motif of mother and child was one of the most important motifs in her entire opus.

(steala) is the answer you are   looking for good luck

they most likely have a instrumental version. just look it up on google.