How many seismographs are needed to find the epicenter of an earthquake? why is this number significant?
answer!

Ineed , i need to create a power point in life science here is a picture explaining a little what the topic is about, me with some information for my slides : (

Iii-eneral sciencewhich of these is the best explanation of how a smooth round stone became smooth? a continuous freezing and thawingbvolcanic actioncit fell off the side of a cliffdit was in a stream for a long time.

Which describes the solid flying debris from a volcano