Congress felt the need to boost American morale by releasing this address in early 1778 because Americans were beginning to lose hope of winning their independence. The address aimed to remind the populace of the cruelties they faced under British rule and to rally support for the cause.
As for the Intolerable Acts, the statement that best describes their effect on the American colonies is that the acts caused the colonies to unify against the British government. This was a pivotal moment that galvanized colonial resistance and led to increased unity among the colonies in opposition to British policies.