Why did Republicans in Congress want to impeach Andrew Johnson?

American sign language is a. not a distinct language by definition b. processed primarily by the left hemisphere, similar to other languages c. processed more or less equally by both the left and right hemispheres d. processed primarily by the right hemisphere because it is based on spatial characteristics

Whether or not a given study has the possibility of causing harm to participants:

Are people more motivated to change from positive or negative experiences, like slavery, womens rights, and any other historical movements/moments? i need more factual information than opinions.