Scientists have measured and recorded the average rainfall of an area over several years to see if there is a pattern. which kind of investigation does this best describe? a. controlled experiment b. systematic observation c. field study d. simulation

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.

Which of the following units is not an official si unit? mole liter kilogram ampere

A) equal lines b) parallel lines c) perpendicular lines d) none of the above