| A | B |
| according to | as stated by someone |
| altruistic | caring about others with no advantage for yourself |
| apply to | to concern or involve someone or something |
| barely | hardly; almost not |
| bring about | to cause |
| bystander | a person who is present when an event happens but who is not part of the event; a witness; an onlooker |
| compassionate | caring about other people’s feelings |
| complex | made up of several connected parts and often difficult to understand |
| end up | to find yourself in a place or situation that you did not intend or expect |
| factor | something that affects a decision or situation |
| hypothesize | to suggest a possible explanation |
| initial | something that is at the beginning; first |
| lead to | to direct or guide; to end in |
| prove | to use facts and evidence to show that something is true |
| rely on | to need and depend on |
| responsibility | a job or duty that you must do |
| subject | person who is part of an experiment |
| theory | an idea or set of ideas that tries to explain something |
| witness | a person who sees something happen and who can tell other people about it later |