Why is it important to only manipulate one variable and to keep
all other variables constant?

The overwhelming majority of the peoples and nations of the world today want to live in peace

Which statement most strongly develops a positive tone? a. i was happy when i received my first paycheck for my hand work. b. winter break is approaching quickly, and i cannot wait to go shopping for gifts. c. going to the beach is one of my favorite activities; i love surfing and paddle boarding. d. a sense of accomplishment overwhelmed me as i stepped into into the stage that sunny, glorious day of graduation.

What is a mechanism by which organisms maintain homeostasis when the level of one substance influences the level of another substance or the activity of an organ.