Which arrow or arrows represent reactions that demonstrate a conservation of mass and energy? Explain your answer

Why are radio observatories located in valleys far away from urban centers? a. to shield them from electromagnetic interference b. to avoid sound pollution c. to avoid disturbing people living in the city d. to shield them from water vapor

What was the effects of the mass demonstrations of strikes that had immediately followed the economic collapse beginning in 1893?

Territorial insects like spiders that fight off intruders would be expected to be