What is a medium?

a. a tool used to convey ideas or information
b. a set of tools used together to communicate ideas
c. tools that are independently connected
d. a tool used to measure important information

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?