A researcher is trying to identify whether household substances are basic. Which approach would BEST help the researcher investigate whether substances are basic?

A. Test each substance with red litmus paper.

B. Test each substance with blue litmus paper.

C. Observe each substance and record its color.

D. Mix each substance with a weak base and record the results.

James is trying to prove newton's 2nd law of motion. he tries to move four different objects with different masses, shapes, and sizes from point a to point b. the objects are a toy car, a car, a refrigerator, and a kitchen table. after some experimentation, he finds that force is dependent on the mass of the object, rather than it's size or shape. the object that takes the most force to move is the

Which of these is the best way to manage a natural resource

When doing scientific research ,the sources used should be ?