Melanie and Lance gathered data about the effectiveness of masks preventing disease. One of the questions they ask the experimental
subjects is their age. What type of observation is this? *

Which instrument is used to measure air temperature

Which statement correctly describes the relationship between frequency and wavelength?

**urgent** roberto plans to use two transformers to reduce a voltage of 120 v to 4 v. he uses a transformer that has 300 coils in the primary winding and 50 coils in the secondary winding. he has four other transformers, as listed in the table. which transformer should roberto use to have an ending voltage of 4 v? a- w b-xc- yd- z