Help ASAP please! Its the last question!

In which research method does a researcher change the value of one variable to determine how the change affects another variable? a. experiment b. observational research c. survey d. case study

The passage below can be revised to make it more concise. which word is a modifier that can be eliminated because it adds no meaning? dr. madison is somewhat skeptical about stories of global warming. she has gathered scientific data in remote areas to prove her position. somewhat global scientific remote

Each of the letters on the map above marks a body of water in southeast asia. which two letters represent gulfs