Why it is important that this ball of cells soon becomes attached to the lining of the uterus?

It is crucial for the ball of cells, or blastocyst, to attach to the lining of the uterus because this attachment, known as implantation, is essential for establishing a successful pregnancy. This process allows the growing embryo to access nutrients and oxygen from the mother's blood supply, which are vital for its development. Additionally, implantation triggers hormonal changes that help maintain the pregnancy and prevent menstruation. Without this attachment, the embryo would not receive the necessary support to grow and thrive.