Explanation:

1.  Correct : The bill for the Indian Independence Act was indeed introduced in the British Parliament on July 4, 1947, and received Royal Assent on July 18, 1947. This made it an official Act that outlined the process for the partition of British India and the independence of the two new states, India and Pakistan.
2. Incorrect - The Indian Independence Act did not lay down the basic framework of the Indian Constitution. It primarily provided the legal framework for the partition of British India into India and Pakistan and for their immediate independence. The basic framework of the Indian Constitution was later formulated by the Constituent Assembly of India.
3. Correct - The Act provided for the partition of British India and the establishment of two independent Dominions, India and Pakistan, effective from August 15, 1947.
4. Correct - The Act empowered the Constituent Assembly of each new Dominion to frame its constitution. These Assemblies were sovereign bodies with the power to draft, adopt, and enact constitutions for their respective nations.