4. What did Congress use to investigate the government, armed forces, unions,
education, science, newspapers, and other aspects of American life?
A the 1957 case of Watkins v. United States
B the House Un-American Activities Committee
O
the 1940 Smith Act
OD the Hollywood Ten

Congress use the House Un-American Activities Committee to investigate the government, armed forces, unions,  education, science, newspapers, and other aspects of American life.

Explanation:

The House Un-American Activities Committee(HUAC) was made in 1938 to explore affirmed traitorousness and incendiary exercises with respect to private residents, open workers, and those associations associated with having Communist ties. The United States government reacted by making the  (HUAC), which was accused of distinguishing Communist dangers to the United States. So Congress utilizes the House Un-American Activities Committee to examine the legislature, military, associations, training, science, papers, and different parts of American life.

i would say the executive branch is because the executive branch is in charge of enforcing the laws and judicial branch is in charge of enforcing but the executive branch is most responsible for it all so i would have to say the executive branch.