No.

In 1947, the United Nations, not the United States, adopted a plan calling for the division of the British Mandate of Palestine into a Jewish and Arab States. The United States supported this Resolution but did not "adopt" it.

Yes. In 1947, the United Nations General Assembly adopted Resolution 181.

There are 192 members in the general assembly.

The United Nations General Assembly.

On November 29, 1947, the United Nations General Assembly adopted UN Resolution 181 which specified that Mandatory Palestine would be divided into an Arab State and a Jewish State. However, the plan was only actualized in May of 1948 when the State of Israel declared independence according to the terms prescribed by UN Resolution 181.

The question seems to be looking for the answer "the United Nations General Assembly", but that is actually not quite correct.

In November of 1947, the United Nations General Assembly adopted UN Resolution 181 which specified that Mandatory Palestine would be divide into an Arab State and a Jewish State. However, the plan was only actualized in May of 1948 when the State of Israel declared independence according to the terms prescribed by UN Resolution 181. So, the plan was adopted in 1947, but realized in 1948.