Who invented the idea of tempering metal to make it stronger

Which of the following studies is linked most directly to the establishment of the national research act in 1974 and ultimately to the belmont report and federal regulations for human subject protection? a. the public health service tuskegee study of untreated syphilis in the negro male.b. stanford prison experiment (zimbardo).c. tearoom trade study (humphreys).d. the harvard t3 study.

How did economics delay scientists' first attempts for conservation in each story? describe the political actions that led to successful conservation in both stories. i have them all done but these two. none of my teachers are responding and i just need . i can show both stories.

Here a fun and extra question will give brainless to the best onehow much wood could a wood chuck chuck if a wood chuck could chuck wood?