negative – adj. not positive or desirable

companion – n. someone you spend a lot of time with

collar – n. a line that attaches around the neck of an animal

stress – n. feelings of worry or nervousness caused by difficult situations or problems

hormone – n. one of several chemicals produced in the body that influence growth and development

pessimistic – adj. tending to believe that the worst will happen

respond – v. say or do something as an answer or reaction to something that has been said or done

boss – n. person who leads a group of employees

motivate – v. stimulate someone's interest or enthusiasm for doing something