Explain what a scientific theory is, and what is necessary to make a theory strong and well supported?

The volume of an unknown substance in a sealed glass jar is 50 milliliters. the volume of the jar is 200 milliliters. which state of matter could the substance be?

Hno2 + caco3 = h2co3 + ca(no2) can someone balance this

How long could you survive without electricity? what parts of your life would be affected by loss of electricity? should you prepare for an electricity outage, and if so, how would you prepare? what backup system could your family or community install to generate limited amounts of electricity during an outage? how does this system create an electric force field and generate electric current?