Illegal border crossings rose by 33% in July, fueled by increase along Arizona desert

Article Quote: "Apprehensions of single adult migrants stood at just over 62,000 in July, virtually the same level as June. Border Patrol also processed more than 10,000 unaccompanied children, nearly a 50% jump from June."
I just can't understand how children can be unaccompanied. Terrorists and other countries are taking advantage of President Biden's Policies. This is not good for the United States of America.