How does Miss Bingley attempt to embarrass Elizabeth in Chapter 45? How does this inadvertently affect Miss Darcy?

In Chapter 45, Miss. Bingley makes no effort to be friendly. She is obviously jealous of Mr. Darcy's regard for Elizabeth, and is even angry that Elizabeth is back on the scene. However, Elizabeth pays no attention to the frequent attempts to throw her off guard, and Mr. Darcy and Georgiana stand up for Elizabeth when she has gone.